
i^^^ 



^ 1 

LIBRARY OF CONGRESS. 

Sh.elf-..dn-- 

UNITED STATES OF AMERICA. 



FIRST LESSONS 



IN 



METAL-W(3RKING 



BY 



ALFRED G. COMPTON, 



PROFESSOR OF AP LIED MATHEMATICS IN THE COLLEGE OP THE CITY OP NEW YORK, 

INSTRUCTOR IN CHARGE OF THE WORKSHOPS OF THE COLLEGE, AUTHOR 

OP " A MANUAL OF LOGARITHMIC COMPUTATION," AND 

OF "FIRST LESSONS IN WOOD-WORKING.''' 




NEW YORK: 

JOHN WILEY & SONS, 

53 East Tenth Steeet. 

1890. 



^^^ 



.g7 



Copyright, 1890, 

BY 

JOHN WILEY & SONS. 



Robert Drummont, 

Electrotyper, 

Ui and 440 Pearl St. 

New York. 










P'ERRis Bros., 

Printers, 

326 Pearl Street, 

New York. 



PREFACE. 



The first year of iustriictioii in handicraft, as 
exj^erience in the College of the City of New 
York has shown, may be given to wood working 
or metal-working with about equal advantage. 
The minute accuracy, the acquaintance with 
geometrical construction, and the habits of neat- 
ness and cleanliness which are essential in the 
one are offset by the judgment, forethought, and 
artistic freedom of the other. Both constantly 
teach the lesson of orderly procedure, careful at- 
tention to instructions, and, where a text-book is 
used, of minute and thoughtful I'eading, such as 
takes in the full significance of every pi'oposition 
and every limitation of it. The feeling of good- 
fellowship which results from struggling with the 
same difficulties, and occasionally, as in wood- 
working, and still mo]*e frequently, as in forge- 
work, lending a helping hand to each other, is 
a valuable part of the product of workshop 
training in either department. It has been the 



111 



iv PREFACE. 

author's practice therefore, for some time, to let a * 
portion of each class begin in the wood-working 
shop, and another in the forge and vise-room. The 
advantao;e is thus secured of having both shops 
well filled ; while otherwise, as the second year's 
class is always smaller than the first, one shop is 
overcrowded at the same time that the other is 
perhaps not more than half full. 

The amount of knowledge of drawing required 
for these lessons is about the same as that given 
in the author's First Lessons in Wood- Working ; 
so that if Metal- Working is taken up first, the stu- 
dent should be taught as much of the latter book 
as is found in Lessons VI, VII, and XXI. 

Considerable thought and space have been 
given to the description and orderly development 
of the processes of manufacture of iron and steel, 
and of the annealing, hardening and tempering 
of the latter. The book being intended, not for 
those who are merely acquiring a trade, but for 
those who are learning to think, and to give clear 
expression to their thought, the lessons on this 
subject are intended to be thoroughly mastered, 
both by study and by practice, so that the student 
shall be able to explain, in good language, the rea- . 
sons of the various processes he uses. 



TABLE OF CONTENTS. 



PAGE 

Preface 

Lesson I. Metal-working Tools, Wrought-iron and Cast-iron, 

Cutting and Breaking 1 

II, Care of Fire, Drawing and Pointing 7 

III. Bending, Turning an Eye. . = 13 

IV. Flattening, Punching, and Bending 18 

V. Pointing and Twisting 22 

VI. Welding 28 

VII. Upsetting and Welding 34 

VIII. Blacksmith and Helper 45 

IX. Welding continued : A Tongue-weld 51 

X. Testing Iron, Manufacture of Cast-iron 58 

XI. Foundry- work 64 

XII. Manufacture and Properties of Wrought iron 71 

XIII. " " " " Steel 75 

XIV. Welding Steel : Low Grade 81 

XV. " " High Grade 85 

XVI. Hardening and Tempering Steel 88 

XVII. " " " " 98 

XVIII. " " " '' 105 

XIX. Chipping 114 

XX. Drilling and Sawing 126 

XXI. Filing 132 

XXII. Soldering — Bunsen Burner 148 

XXIII. " The Soldering-iron 157 

XXIV. " Blow-pipe 165 

Alphabetical Index 169 



FiEST Lessojsts 



IN 



METAL-WORKING 



LESSON I. 

METAL-WORKING TOOLS. WROUGHT-IRON AND CAST- 
IRON. CUTTING AND BREAKING. 

The tools used in cutting iron, like those used 
in wood- working, are wedges. They are thrust 
in or driven in between the j)articles of the metal, 
separating them from each other, making notches 
in the piece, and, if they penetrate far enough, 
tearing off chips or cutting the piece in two. 
Metal being much harder than wood, it is gener- 
ally necessaiy to drive the cutting-tool forward 
by blows of a hammer, as is the case in wood- 
working also when the cut is deep or across the 
grain of the wood. When the metal and the 
tool can be held in powerful machines, such as 
the engine-lathe and the planing-machine, which 
you will understand by and by, a steady push can 



2 FIRST LE880N8 IN METAL- WORKING. 

be used, but without these, blows of a hammer 
are generally necessary. 

Again, metal being much harder than wood, a 
different form has to be given to the cutting-tool. 
For wood-working the wedge may be thin, and 
therefore can be made to penetrate easily. The 
two faces of a knife, hatchet, or chisel make 
with each other an angle of about 25°, which is 
increased to 35° near the edge, by the sharpening 
of the tool on the oil-stone. Even this is some- 
times fonnd to be too small, and the tool splinters 
or "nicks" when cutting hard w^ood. For iron, 
therefore, the angle must be larger than this. It 
need not be much larger if the tool is not very 
brittle and if it is used only for cutting straight 
forward ; but when the metal of the tool is very 
hard, or when the tool is strained crosswise in 
cutting, the angle must be larger, and is, in some 
lathe-tools, as great as 90°. 

Again, metals b^ing very hard, metal-tools are 
much heated if driven fast. It is a familiar fact 
that rubbing, compressing, or tearing asunder 
any material produces keat. Wood is heated by 
repeated blows of a hammer. In boring holes, 
the w^ood and the bit become hot. When the 
material worked is so hard as iron, if tools are 
pressed against it hard enough to cut it and then 
are moved rapidly, a great deal of heat is pro- 
duced. In this case the heat may be enough to 



METAL-WORKING TOOLS. 3 

soften and spoil tlie tool, and it is necessary 
therefore to work more slowly. 

In metal- working there is no operation like that 
of splitting or hewing: chipping, which comes 
nearest to it, is considerably slower. In all metal- 
workingj therefore, the pieces are fashioned nearly 
to the desired shape while they are soft, and the 
work which the cntting-tool has to perform is 
thus lessened. There are two ways in which the 
metal is thns prepared — casting and forging. 

Casting is melting the metal and pouring it 
into moulds of the proper shape. In this case 
heat performs the greater part of the work. It 
separates the particles of the metal from each 
other so that they can flow into every corner of 
the mould, and the workman has then only to 
finish the surface of the casting with suitable tools. 

Forging is hammering the metal while it is 
soft. All metals melt when heated. The tem- 
perature for melting ranges from about 450° F. 
for tin to about 4500° F. for platinum. Before 
reaching the melting-point, the metal becomes 
soft, and, while in this state, if two perfectly 
clean surfaces are brought into close contact, they 
adhere and the two pieces become one. This 
process is welding. While in the soft state also, 
a metal can be hammered into almost any desired 
shape. This process is forging. The two pro- 
cesses of forging and welding are generally in- 



4 FIRST LE880N8 IN METAL-WORKING. 

eluded under the term "forge-work" or ^^ forging." 
They are applicable, as casting is, to various 
metals ; but all three are important chiefly in 
the case of iron and steel, because of the ease 
with which the operations can be performed, 
and the abundance, cheapness, and strength of 
the metals. 

The iron used for casting, or foundry-work, 
and that used for forge- work, are called respect- 
ively cast-iron and wrought-iron. Cast-iron is 
iron combined with carbon ; wrought-iron is the 
same metal after as much as possible of the car- 
bon is removed. We will begin our exercises in 
forge-work by studying some of the differences 
between them. 

Examine the two specimens of iron on your 
anvil. Holding each loosely between the fingers, 
strike it on the edge of the anvil. Observe the 
ringing of the one and the duller sound of the 
other. Strike them on the edge with the edge of 
vour hammer, and observe the difference in the 
character of the nick. Lay them on the anvil, 
and hammer them pretty vigorously at one end. 
One flattens, the other does not ; one is malleable, 
the other is not. When you have learned to use 
the fire, repeat this lasfc experiment while the 
pieces are red-hot, and you will find the difference 
greater still. Lay them across two supports, 
about 3" apart on the anvil, as in Fig„ 1, and 



METAL-WORKINO TOOLS. 



strike tliem with the liammer (being careful not 
to stoop over them, lest they iiy up and hurt you). 




Fig. 1. 

One bends, the other very probably breaks.* 
Next try to break the bent one: you find this 
difficult. At one end of the anvil is a chisel, 
called the "hardee" or " hardy," mean- Exercise i. 
ing ^' hard edge," being made of steel. Cutting with 
and hardened on the edge. Lay the *^® i^a^dee. 
unbroken piece over this, and strike it two or 
three times with the hammer, making a nick in 
it. Be very careful not to strike the hardy with 
the hammer. Turn the piece over, and nick the 
other side, exactly opposite the first notch. When 
you have cut it thus, you wdll find that you can 
break it by laying it over the two supports, and 



* The same experiment may be made with less risk of injury from 
the flying fragments when the piece breaks, by holding each piece 
in the vise while striking the blow. Let it project three or four 
inches above the vise. Strike from you, towards the wall behind 
your bench, so that, if the piece flies olf, it will hit no one. Or, still 
more safely, the pieces may be bent by holding them at the ends in 
a suitable clamp, and pressing them down at the middle by a screw. 



6 FIRST LESSONS IN METAL- WORKING. 

strikinof it at the nick, or even, if it is notched 
pretty deeply, by laying it over tlie edge of tlie 
anvil, and striking it just beyond the notch, or 
holding it in the vise, just below the notch, and 
striking at the end. The tough piece is wrought- 
iron ; the brittle piece is cast-iron. Make a writ- 
ten memorandum of all the differences between 
them that you can discover, including the differ- 
ence between the surfaces of fracture examined 
with a lens. 



CARE OF FIRE. DRAWING AND POINTING. 



LESSON 11. 

CARE OF FIRE. DRAWING AND POINTING. 

When an object is made of wrouglit-iron, it 
must be made as nearly as possible of the I'ight 
shape at first, by forging, so that it may require 
little or no finishing with cutting tools. Forging, 
or shaping with the hammer, includes a number of 
distinct operations, called drawing, pointing, up- 
setting, bending, twisting, punching, and welding. 
In nearly all of these the first step is to make the 
metal red or white hot, and in doing this the 
proper management of the fire is of the highest 
importance. 

Your forge has a broad "hearth," on which 
coal can be heaped up over the mouth of a 
pipe called the "tuyere" (pronounced twee-er). 
Through this tuyere a current of air can be forced 
from the bellows or blower. With a moderate 
supply of air the fire burns slowly, and produces 
a temperature of about 800° or 900° C, equivalent 
to about 1500° co 1700° F. Every atom of oxy- 
gen that unites with an atom of cai'bon in the coal 
pi'oduces a cei'tain amount of lieat ; hence the 
more carbon and oxygen used, the more heat pro- 
duced. With a good supply of air you can raise 



8 FIRST LESSONS IN METAL-WORKINO. 

your fire, and any piece of iron in it, to about 
1500° C. or 2700° F. It is possible, however, to 
f urnisli nlore air than tbe carbon requires for its 
combustion. The air then only cools the carbon, 
or tends to blow out the fire. A lighted stick 
thrust into a bottle goes out for lack of oxygen. 
A lighted match goes out in a strong draught 
because of excess of air. Remember this in man- 
aging your fire. 

To start your fire, place a small heap of shav- 

Exercise 2. ^^S^ ^^^^ ^^^ throat of the forge. 
Making a Light it, and when it is blazing, scrape 
^®* a few pieces of coke or coal over it, 

choosing such as is free from large lumps. As 
these light, scrape on more, blowing gently with 
the bellows. Gradually cover completely, and 
blow hardei-. Sprinkle with water the coal round 
the outside of the fire, which will prevent the fire 
from spreading too far, and will also make coke 
for the next day. When once started, the fire 
can be kept covered and burning slowly for a long 
time, by leaving a stick of hard wood in it, or can 
be blown up in a few minutes to a white heat. 

For your first exercise in forging, cut off a piece 
of ^" round iron, exactly 20'' long. If you fail to 

Exercise 3. ^^^ ^^ exactly right, make a memoran- 
Heating to a dum of the length in your note-book, 
w 1 e ea . ^^ ^^^|j| ^^^ make a square point 

two inches long on the end of this. Put the end 



CARE OF FIRE. DRAWING AND POINTING. 9 

in the fire, covering it liglitly with the coals. It 
is best, particularly in working such thin iron as 
this, not to bury it very deeply in the fire, but to 
keep it near the surface, where it can be watched 
through the spaces between the coals, and re- 
moved as soon as it reaches the proper heat. If 
left too long in a very hot fire, and with a plenti- 
ful supply of air from the bellows, the iron may 
burn and the piece be spoiled; for iron is combus- 
tible, just as wood and coal are, only it requires 
a higher temperature to burn it. With larger 
pieces, such as you will have in later exercises, 
this accident is less likely to happen. Watching 
your iron, you w^ill see the black rod get gradually 
red and then white, so as to be indistinguishable 
in the midst of the glowing fuel. In this condi- 
tion it will burn if left too long. Remove it from 
the fire by the cool end, which will be cool enough 
if you have not thrust it in too far, or left it too 
long. It should be white-hot just at the end, and 
red about two inches farther. As you carry it 
through the air, brilliant white sparks will shoot 
off from it, if it is at a good white heat : these 
are particles of iron burning. Lay it, without loss 
of time, on the anvil, so that the hot end rests on 
the farther edge, the end in your Exercise 4. 
hand being raised three or four inches, Drawing and 
so that the bar is inclined to the face p°^"*^^&- 
of the anvil. Hold the hammer with its face 



10 FIRST LESSONS IN METAL-WORKINO. 

similarly inclined. Grasp it firmly, with the 
fingers under the handle and the thumb ex- 
tending along the top. Then, with quick 
light strokes, not near the end, but at the 
very tip, beat the iron out, turning it to and fro 
through a quarter turn after each blow or two, so 
as not to flatten it, but to make the end square 
and pointed. When a little of the end is 
pointed, you may gradually w^ork farther back, 
till you have produced a square point two inches 
long. Be careful not to continue hammering, 
particularly at the point, after the iron has 
lost its bright white heat. If you do this you 
will probably split it. Wrought-iron, as we 
shall see later, is fibrous in structure, and the 
fibres, like those of wood, can be toru asunder 
more easily than they can be broken across. This 
splitting is especially liable to happen in inferior 
iron, just as it does in wood that is wanting in 
toughness, and affords one means of judging of 
the quality of the iron. If your rod does split at 
the end, you can generally get the parts to re- 
unite, by raising it again to a white heat, and 
hammering gently. This operation is assisted by 
sprinkling the piece with white sand when you 
take it from the fire, and putting it back in the 
fire a few minutes before hammering it. If you 
do not succeed in closing the split, you must cut 
off the cracked end on your hardy and begin 



CARE OF FIRE. DRAWING AND POINTING. 11 



again, being more careful now to keep the metal 
at a bright red heat when hammering near the 
end, reheating it for this purpose several times if 
necessary. 

In turning the piece to and fro while hammer- 
ing, you must be careful to give it just a quarter 
of a turn each time ; otherwise you will give it the 






Fig. 2. 

cross-section a, Fig. 2, instead of h. In this case 
you will have considerable trouble to restore the 
proper shape by holding it on the anvil as at <?, 
and striking it at d. 

When you have pointed the piece and cooled 
it, measure its length, and compare it with the 
length it had at first. The lengthening of a piece 
by hammering is called drawing. Observe how 
much you have drawn this, making allowance for 
any that you may have cut off because of splitting. 
It is important that you should learn to estimate 
the amount of drawing in any particular case in 
order to be able to make allowance for it in future 
work. Of course this lengthening cannot be ac- 
complished without reducing the diameter, either, 
as in this case, at the point, or at some other place, 



12 FIRST LESSON'S IW METAL-WORKING. 

or along its whole length. This last is what takes 
place in making " bar-iron." A short thick mass 
of iron is passed, while white-hot, between strong 
rollers such as are shown in Fio^. 52. As the iron 
passes through the successive grooves, it is reduced 
in thickness and increased in length, and comes 
out at last as bar-iron, of the same size and shape 
as the last groove. 



BENDING. TURNING AN EYE. 



13 



LESSON III. 



BENDING. TURNING AN EYE. 

Having drawn and pointed the rod, form an eye 
on it, as in Fig. 3. The eye, being 1'' in diameter, 
will be nearly ^^" in circumference. 




1 

I 
I 



Fig. 3. 

Heat about 3 J'' of the end of the rod to a bright 
red heat. Lay it over the edge of the anvil, with 
one of the flat faces of the point tui'ned U23, and 
bend it down at right-angles with a few gentle 
blows of the hammer. 

Strike at a and h, Fig. 4, alternately, striking 




Fig. 4. 



from you as well as downward, so as to give a 
kind of pushing blow, till you have a good square 
bend. Do not hit with the edge of the hammer, 
nor hard enough to bruise the iron. . 



14. FIRST LE8S0NS IN METAL-WORKINO- 

Next place the part h on the '' horn," or round 
end of the anvil, as in Fig. 5, and bend it round 
as at c and r/, nearly closing the ring. Then, 
laying the part ho on the edge of the anvil, the 





Fm. 5. 



point d being upward, and striking lightly at d, 
close it. Be careful to make the ring as nearly 
Exercise 5. as possible circulaiv . pei#otly closcd, 
Bending. .^^^ Symmetrical on the stem, as at /, 

Fig, 6, not one-sided, as at g. The last part of 
the eye, near the point of closing, must be bent 
with the tail or " pene" of the hammer. If you 
do not succeed the first time, heat the eye again, 
spread it out by driving it on the horn of the 
anvil, and repeat. 

If the eye closes too far dowm on the stem, as at 



BENDING. TURNING AN EYE. 



15 



a^ Fig. 7, open it on the horn, and then bend it to 
the proper shape with light blows of the tail of 
the hammer at h^ while resting on the horn at c. 
If it closes too far up, as at d, strike at /, while 
resting on the horn at e. If the iron gets too 
much burned, you must cut it off on the hardy 






Fig. 6. 



Fig. 7. 



and begin again ; but this ought not to occur, as 
it spoils the proportions of the piece. 

Use the eye already formed, if it is a good one, cut- 
ting off the square point on the hardy. Exercise 6. 
If it is not good, cut off another piece of a forge- 
bar-iron of the proper length, and form a P° 
new eye. Flatten the rod for about 4'' from the 
end, to a width of about %", which will give a thick- 
ness of about ^". In flattening, or in any operation 
in wdiicli much hammering is to be done on one piece, 
do not move the hammer about on the anvil, l^ut 
let it fall constantly on the same point, about the 
middle of the face of the anvil, and move the iron 



16 FIRST LESSONS IN MET AL- WORKING. 

instead of tlie hammer. This principle is even more 
important when two persons work on the same 
piece, as in some later exercises. Hold the rod so 
that the plane of the flattened portion shall be 
perpendicular to the plane of the eye. In this, 
as in Exercise 4, page 10, begin hammering at the 
tip, and with a good bright w^hite heat, so as not 
to split the rod. Having flattened it to the 
proper amount, hammer it cold, to smooth it. 
Heat it again, lay it over the edge of the anvil and 
bend it at right angles at a, Fig. 8, as in Exercise 





Fig. 8. 

5, Fig. 4. Lay it across the horn and bend the 
curved part ha. Again lay it on the edge of the 
anvil as at c?. Fig. 9, and form the straight end as 
at d. The plane of the bend should be the same 
as the plane of the eye. Look along the rod and 
test this. See also whether the rod is straight, 
and whether the plane of the shoi't flattened piece 
at the end is perpendicular to the plane of the 
bend and the eye. Correct any crookedness by 



BENDING. TURNING AN EYE. 



17 



gentle blows while the iron is cooling. If the 
plane of the flattened portion is not perpendicular 
to the plane of the ring and of the curve ah^ heat 
the straight part near ab to redness, place it on 




Fig. 9. 

the anvil so that the eye is perpendicular to the 
face of the anvil, and strike a light blow or two at 
h. Or hold the ring in the vise, and, taking hold 
with the tongs at Z>, twist the I'od to the proper 
position. 



18 FIB8T LESSONS IN METAL-WOEKING. 



LESSON IV. 

FLATTElS^INa, PUNCHIl^G, AIN^D BENDIIS^G. 

While iron is soft it is easy to maka holes in it 
of any desired shape, with a steel punch. 

We will make an '^ angle-iron " or " bracket," 
Fig. 10, from a piece off round iron 8'' long. 

This is to be first ham- 

@ ® I mered out flat to a width 

^" of h"\ secondly, bent at 

^ ' right angles ; and, third- 

ly, punched with four 
holes for screws. Take 
a piece of ii'on 16 long. 
For the first operation, 
heat one end of the 
piece to whiteness, and, 
beginning as in Exercise 
^i«- 10- 4, page 10, at the end, 

and with the same care to prevent splitting, hammer 
it down to the thickness of about \". Then, work- 
ing from the end towards the middle, flatten about 
^" of the piece, w^orking always on the centre of 



FLATTENING, PUNCHING, AND BENDING. 19 

the anvil, as iu Ex. 6. Be careful not to hammer 
more on one edge than on the other. If you do 
you will bend the piece. If, for instance, you 
hammer too much on the I'ight-hand edge, you 
will make this edge not only thinner, but longer 
than the othe]', and will thus make the piece bend 
towards the left. If you find this happening, you 
can correct it by hammering a little more all along 
the left-hand edge, or w^herever you find it thicker 
than elsewhere. Turn the piece over occasionally, 
and hammer on the other side to prevent the end 
from turning up. Heat about four inches more 
of the bar, and flatten in the same Avay the rest 
of the 8" that will be required. Do not extend 
the flattening more than about a quarter of an 
inch be3^ond the required distance. The remain- 
der of the metal was only left as a handle to hold 
the piece by, and when you have finished, is to be 
cut off and left undefaced for future use. 

The piece is now of the unifoi'm w^idth of ^" 
straight and uniformly thick, and is ready for 
bending and punching. Before bending, bevel 
the edges slightly on the side where the heads of 
the screws will be, by hammering, cold, on the 
anvil. Mark with a centre-punch. Fig. 11, b, the 
place at which the bend is to be made. Heat the 
piece to a red heat at this place, lay it on the an- 
vil with the mark exactly over the edge, and, 
while an assistant holds a hammer on the piece 



20 FIBST LESSONS IN METAL- WOBKINO. 

just beMnd the mark, bend it at right angles. 
Or, hold it in the vise at the mark and bend it. 

For punching, use a slightly tapering punch, 

Fig. 11, A, about jY' in diameter at the point, 

and not more than J'^ at one inch from the 

end. Havino; marked with a centre- 

Exercise 7. punch the places where the holes 

Punching. ^ ^ . i , t 

are to be made, lay the piece, heated 
to a bright red, on the anvil, and drive the punch 
half-way through. The piece, when turned over. 



a 



a 



Fig. 11. 

will show a dark spot due to the cooling effect of 
the punch. Apply the punch here and drive it 
through from the other side, pushing out the 
small piece or burr by driving it into one of the 
holes in the anvil. Be careful not to drive your 
punch in too far, or you will spread the hole too 
wide, and may split the piece. Drive it so far as 
to enlarge the hole enough for the admission of 
the screws that are to be used in putting up the 
bracket. If these are " round-headed " screws, 
Fig. 12, A, this is all that it is necessary, except to 
smooth and straighten the piece where it may 
have been bent. If they are '^Hat-headed," Fig. 
12, B, the holes must be "counter sunk," that is, 



FLATTBNINO, PUNCHINO, AND BENDING. 



21 



enlarged at the top, as in Fig. 18, to correspond 
with the head of the screw, and let it come even 
or ^' flush" with the sui'face of the „ . o 

Exercise 8. 

iron. Wlien only a shallow counter- Countersink- 

sink is required, it may be made with ^^^' 

a countersink-punch. Fig. 14, a; but to cut deep 







Fig. 12. 



Fig. 13. 



<f=^ 



enough to let the head of a screw come even with 
the surface of the iron, a countersink-bit, Fio;. 14 
B, must be used, as in wood- working. 

When you have made and countersunk the 
holes, iinish the piece as straight and smooth as 
you can, cold. Finally, cut it oif 
at the proper point, and bevel the 
newly cut edge like the others. 
When finished, the bracket should 
be true to the proposed dimensions, 
exactly light-angled and free from 
^^ winding," smooth and- without 
marks of burning, square at the 
ends and equally bevelled all 
round, and the centres of the 
holes should be in a line exactly parallel to the 
edges. 



A B 

Fig. 14. 



22 



FIRST LESSON'S IN METAL- WOBKINO. 



LESSON V. 

BENDING, POINTING, AND TWISTING. 

Eemembeeing how much the iron was di*awn in 
Exercise 4, provide a piece of \'' round iron of the 
proper length for the exercise shown in Fig. 15. 




(FuUSize) 



Fig. 15. 



Keep a memorandum of the length j)rovided, and 
test the correctness of your estimate by compari- 
son w^ith your finished w^ork at the end of the 
exercise. 

The iron in this exercise being short, will have 
to be held with the tongs. Point both ends of 



BENDING, POINTING, AND TWISTING. 



23 



Exercise 9. 
A staple. 



the piece, as in Exercise 4, with the precautions 

there indicated. Make the flat sur- 

fac( > at the two ends to match. Heat 

the piece at the middle and bend it Use of the 

over the horn of the anviL Attend 

to the following points : 

1. Hold the tongs so that the opening between 
the jaws shall be horizontal. One of the jaws 
will then be over the piece you are holding, which 
will then not be so easily knocked out of the 
tongs as if the opening were vertical. 
- 2. Let the bend be in the plane of two of the 
squared faces. 

3. Make the bend as nearly as possible in the 
middle. 

In making the bend you will probably bring 
the points too near together; in fact they may 
almost meet. To separate them, drive the staple 




Fig. 16. 

down onthehardee, so that the latter shall spread 
out the legs. If they are not quite ecjual, make 
them so by striking gently on the curve while 
holding the staple upright with the point of the 
long leg resting on the anvil. Straighten the 



24 FIRST LESSONS IN METAL-WORKING 

legs by thrusting tlie thin end of the anvil be- 
tween them as in Fig. 16, and hammering lightly 
first one and then the other. Lay the staple on 
the anvil and see that the legs lie in the same 
plane, both touching the face of the anvil in their 
whole length. If they do not, hold one end in 
the tongs and strike the other near the top or 
circular end till you correct the winding or twist ; 
or you may hold one end in the vise and bend the 
other to the proper position with the tongs, or, 
when cold, with the fingers. Examine the curve 
carefully for any lack of symmetry, and correct it 
by gentle blows over the horn of the anvil. 
Finish it smooth when cold. Do not neglect to 
compare your finished work with your estimate, 
so as to learn how much to allow for such objects 
in the future. 

Each ring in this exercise being 1\'' in diame- 
ter, the circumference will be 3^ times 
Exercise 10. ^^n ^ or about 4'', and both together 
about 8''. A portion of the iron, about 
\", at the middle, belongs to both rings. Deduct- 
ing this, and about \'^ to fat each end for draw- 
ing, leaves about 6^' as the length of the piece 
of \'' iron needed for the Job. Holding the 
piece with the tongs, point each end, as in Ex- 
ercise 4, but round instead of square. It will be 
a useful exercise, and will assist you in rounding 
the iron symmetrically, to make it first square, 



BENDING, POINTING, AND TWISTING. 



2b 



tlien octagonal, and then round. Do not make 

the points too long. If the taper 

extends beyond a, Fig. 17, it will 

weaken the hook. Be careful not 

to burn the points. Finish them 

smooth, cold. Then, heating one 

end to redness, lay it on the horn 

at the middle of one half, or 

a little nearer to the middle 

of the piece, as at 6>, Fig. 18, 

and turn it as in Exercise 5. Having formed one 

eye, heat the other end and form the other in the 




Fig. 17. 



Fig. 18. 



same way. The points of the hook should be 
bent down almost to the stem, as at c, Fig. 17, 
leaving an opening of about ^'\ 
Both eyes should be exactly circu- 
lar and equal, the hook appearing 
as in Fig. 17, not as in Fig. 19, 
where ah is too nearly straight, and 
the eyes are too pointed at c. 

You have now disco veered that 
forge- work requires more judg- 
ment by the eye than wood- work. 
It is not possible to mark out your work with 
rule and square. You must estimate without the 




Fig. 19. 



26 FIRST LESSONS IN METAL- WORKING. 

help of these tools, and must make allowance for 
changes of size which the pieces undergo in draw- 
ing, and in other operations to be described here- 
after. 

Estimate the quantity of iron needed for the 
hook, Fig. 20, making allowance for the length 
4>:ained in drawing, and cut off a suitable piece. 
Then proceed as follows : First draw 
Exercise 11. ^^^ round the point as in the last ex- 
ercise. Next bend at right-angles at 
a, as in Exercises 5 and 6. Then turn the curve h 
over the horn of the anvil, and form the flat curve c. 




-5 ■ 



^ 



Thickness }A' 

Fig. 20. 




Lastly, form the eye as in 5 and 6, being care- 
ful to have it in the same plane as the hook, and 
circular, and symmetrical on the stem. In all 
these exercises care must be taken to keep the 
iron hot enough to w^ork easily, but without burn- 
ing it. A bright white heat is needed for draw- 
ing and pointing, and a good red heat for the rest 
of the Avork. In all the operations also, care is to 
be taken not to mar the cylindrical form of the 



BENDING, POINTING, AND TWISTING. 



27 



iron by hammering too hard ; and in all of them, 
any parts that have been roughened by the heat 
should be hammered cold to smooth them, but 
not so hard as to injure the iron. Examine your 
work critically, looking along it to test for wind- 
ing, and not accepting it as finished so long as 
there is any particular in which you can improve 
it. Finally, compare its dimensions carefully 
with those of the working-sketch, so as to learn 
whether your allowance of metal was correctly 
made. 

The following is a variation of the last exercise, 
involving squaring and twisting. The dimensions 
are given in centimeters. The thickness of the 
iron may be the same as in the last ex- Exercise 12. 
ercise. After pointing the rod, form a twisted 
the hook and the eye as in the last ^°°^' 
exercise. Then square the part ah^ Fig. 21, with 



< 



^l-Si'ii.-- 



I 




Fig. 21. 



the same precautions as in Ex. 4. Finish the 
square part cold, with good sharp edges. Then 
heat to redness, and cool both ends in water, 
leaving about ^^" in the middle bright red (not 



^8 Fimt LESSONS IN METAL-WOMKINQ. 

white, which would soften the iron too much). 
Holding it upright in the vise by the lower end, 
take hold of the other end with the tongs, and 
twist it round rather slowly, through exactly two 
turns, leaving the plane of the eye coincident 
with that of the hook. Be careful not to bend 
the stem in twisting it, as it will be hard to 
straighten it without defacing it. 



WELDING. 29 



LESSON VI. 

WELDING. 

WELDmo is joiniDg two pieces of metal which 
have been made soft or pasty by heat. Wrought 
iron, if of good quality, comes to this condition at 
the temperature of about 1500° C, or about 2700° 
F. This temperature is called the" welding heat," 
and may be recognized by the dazzling white 
light that the iron gives off, and the vivid sparks 
that fly from it as it is carried through the air to 
the anvil. If the 'iron is not of good quality it 
may be made brittle by heat. Such iron is 
called "hot-short" iron. No such iron must be 
used. Indeed, it is hardly possible to use it, but 
valuable time may be wasted in trying to do so. 
Iron which breaks under the hammer when cold 
is called "cold-short." 

The sparks given off by iron at the weldiug 
heat show that it is burning, and therefore wast- 
ing away. This high temperature therefore must 
not be used, except when it is absolutely necessary, 
as in welding ; all other operations of the forge are 
performed at a "white heat," a "bright red or 
cherry red," a " low red," or even a " black red," 
which is only visible in a dark place. 



30 FIRST LESSONS IN METAL- WORKING. 

When two pieces of wrouglit-iron are to be 
welded together, they must both be brought to 
the welding heat ; and they ought to reach that 
heat at the same time, otherwise one may be 
burned before the other is ready. They, should 
therefore be heated in the same part of the fire, 
and should be watched, and if necessary moved 
about, to let each receive its proper amount of heat. 
When at the welding heat, they must be put to- 
gether as quickly as possible in the proper posi- 
tion, and made to adhere by a few light blows of 
the hammer, after which harder blows are given 
till the union is complete. 

To hold the two pieces in the 23roper position 
and manao^e the hammer at the same time is often 
difficult, and, even if the pieces are not very large, 
generally requires the hands of two men, unless 

















^ --'- 1 ' 














II 














«/* ■ — ■ - 






— > 




1 1 

1 1 
1 


if 













Fig. 22. 



some device be used for fastening the two pieces 
toscether. We will therefore beo^in our exercises 
in welding with such as consist in joining the 



WELDING. 31 



ends of the same piece, and so do not requii-e an 
assistant. The forging of an old-fashioned eye 
for a gate-hinge, Fig. 22, is such an exercise. To 
make the piece of the dimensions indicated in the 
figure, cut off a piece of f " round iron b" long. 
This is to be first flattened and shaped Exercise 13 
as shown in Fig. 23. The drawing of Flattening 
the ends must be done at a red heat. If ^^^ drawing, 
a white heat is used it w^ll be harder to make the 
weld afterwards. Turn the ]3iece over frequently 



-93<- - 



Fig. 23. 

while working it, to keep it straight. Do not 
make it too thin at the ends. When flattened, it 
should have in the middle the shape and size shown 
in the section, nearly, being flattened Exercise 14 
less than it will be in the finished job. An eye for a 
for fear of weakening it too much, and ^^"5®- 
increasing the risk of burning. Reheat the piece 
as often as may be necessary, but take care not 
to burn it. If you are pretty skilful, one or two 
heats will be enough to bring it to the proper 
shape. Hammer the edges square, keeping the 



32 FIRST LES80N8 IN METAL-WORKINO. 

corners sharp and smooth : good edges are as es- 
sential to fine workmanship in metal as in wood. 

Next, heating the piece to a dull red at the mid- 
dle, hold it at one end with the tongs, and bend it 
round the horn of the anvil till the two parts are 
parallel and equal, as in forming the staple. Exer- 
cise 9. Put a piece of f ^^ round iron in the bend, 
and hammer the two parts close together, as at a, 
Fig. 22, laying the piece on the anvil with the eye 
overhanging the edge, and striking lightly with 
the tail or "pene" of the hammer. The two parts 
must be in as close contact with each other as pos- 
sible, otherwise dirt will get in between them, and 
may spoil the weld. 

The piece is now ready for welding. Raise it 
to the welding heat. It is very essential for this 
operation that you should have a good bright 
fire, made of fresh coals, free from the burnt-out 
cinders on the hearth. These will not burn well 
enough to secure a good welding heat, and besides 
will make the surface dirty. The throat of the 
forge also must be cleared of the solid cinder 
which forms there, and the fire must be deep 
enough to contain a good body of coals under the 
iron as well as over it. When the piece is at a 
dazzling white heat and throws off brilliant sparks 
in the air, place it, with the least possible loss of 
time, on the anvil, and hammer it quickly with 
moderate force and beginning at the point, till it 



WELDING. 33 

is welded to within about \^' of the eye. Heat 
the eye to a dull red, drive iu a round tapering 
punch \" in diameter where thickest, and hammer 
harder, at a dull-red heat, to flatten the metal 
here and smooth the eye inside and outside. If 
you have not a proper punch, make one, from a 
piece of \" round iron by drawing and pointing it 
slightly, as in Exercises 4 and 9. If the eye is too 
pointed at the base, close it by hammering on the 
edi2:e of the anvil with the tail of the hammer 
while the punch remains in place. The eye should 
be perfectly round and smooth. Finish the shank 
straight, square, and smooth, and draw the tip 
down to a sharp point. Compare your finished 
work with the figure, observing how much you 
have departed from the proposed dimensions. If 
your piece has turned out too short, it is because 
you have burned it, or not drawn it out enough, 
or both. Ascertain the cause of your error, and 
work closer the next time. 



34 FIRST LESSONS IN METAL- WOBKING. 



LESSON YII. 

UPSETTES^a AND WELDING. 

The next exercise, the forging of a link of a 
chain, is similar to the last, in that the two surfaces 
of the weld belong to the saroe piece, and thus 
again the need of a helper is avoided. The weld, 
however, is much shorter, and so the surfaces of 
contact are smaller. Besides, as the link of a chain 
is subject to great stress, it is even more important 
in this case than in the last, that the union of the 
two parts should be perfect. This therefore will 
be a more difficult task than the last. ' 

Use the piece of i'' iron, 8'' long, left from Ex- 
ercise 7. The joint is of the form called a scarf- 
joint, and is shown in Figs. 25 and 28. The sur- 
faces may be prepared either before or after bend- 
ing the piece, but it is somewhat easier to make 
them fit together well if prepared afterwards. 
It will be necessary, however, to provide against 
the waste which will occur at the joint by thick- 
ening or " upsetting" the piece at the ends. This 

is an operation which has often to be 
Exercise 15. performed as preliminary to others. 

It may be done either before or after 
the bending. To perform it before bending, heat 



UPSETTING AND WELDING. 35 

about one inch of the end of the bar to whiteness. 
If much more than an inch is heated, cool it, by 
immersing the bar, up to within about an inch of 
the hot end, in water. Then "upset" the piece 
eitlier by striking the hot end on the anvil while 
holding it npright in the tongs, or by standing the 
piece npright on the anvil, holding it with the 
tongs w^ith the hot end up, and striking the latter 
w^ith the hammer. In either case the blows must 
not be too hard or the piece will bend. The same 
will ha23pen also if too much of the length of the 
piece is heated. If the piece does bend, it must 
be straightened before going any farther. If the 
hammerino^ turns the metal over too much on the 
edge, lay the piece on the anvil and hammer it 
gently on the sides, but only enough to smooth 
the ragged edge, without reducing the end to its 
original thickness. When properly upset the end 
should appear as in Fig. 24. After upsetting one 






Fig. 24. 

end, cool it, and then heat and upset the other. 
It is obvious that this operation, besides thicken- 
ing the bar will shorten it. You ought to measure 
and keep a memorandum of the amount of this 
shortening, so as to know how much to allow for 



36 



FIRST LESSON'S IN METAL- WORKING. 



it in other cases, wlien it may be necessary that 
the bar should have exactly a given length. In 
the same way that a piece is upset at the end, it 
may, when necessary, be upset at the middle, by 
heating at the middle only, and hammering on the 
end lengthwise. 

The ends being now upset, bend the piece to a 
U -shape. It is then ready for the formation of 
the joint. 

The scarf -joint consists, as the figure shows, of 
an indentation in the end of each piece, into which 
the end of the other piece fits. These indentations 
are not made, as in wood-working, by cutting out 




Fig. 35. 

some of the material, but by hammering it so that 
it spreads out sideways and endways. Neither 
should they, as in the case of the joint in wood, 
be cut to half the depth of the piece, but less. It 
will thus result that when the two ends are put 
together, the piece will be wider and thicker at 
the joint than elsewhere. This extra thickness 
will disappear as the weld is hammered, and if the 



UPSETTING AND WELDING. 



37 



quantity of metal Las been correctly estimated, 
this part will be at last neither thicker nor thin- 
ner than the rest. 

To prepare the scarf, heat the open end of the 
U-shaped piece to a white heat. Lay it on the 
anvil and make a bevel at one end, with the face 
of the hammer, as in Fig. 26. This will still fur- 




FiG. 26. 

ther upset the piece at the upper edge of the 
bevel, as shown in the figure. Then, using the 
pene of the hammer, as in Fig. 27, give the piece 
the form shown, enlarged, at a. The surface need 
not be smooth. It is indeed preferable that it 
should be formed of small ridges or steps as shoAvn. 
Heat the other end of the piece and treat it in the 
same manner, but on the other side. One heat 
Avill be sufficient for the preparation of both ends 
if you work quickly, but there will be no harm 
in heating several times, if you are careful not to 



38 



FIRST LESSONS IN METAL-WOBKING. 



burn the piece. The pieces Avill have Ijeen 
widened in the process of scarfing^ and are to be 
brought back partly to their original width, by 
hammering: on the sides. There should be, how- 
ever, some extra width left, to make up for the loss 
by burning, of which there will be some in spite 
of all the care that can be taken. When finished, 
the scarf will present the appearance shown in 
plan and elevation in Fig. 28. 






^ 




Fig. 27. 



Fig. 28. 



When the scarf has been thus prepared, bend 
the ends of the V round over the horn of the 
anvil as in Fig. 29, till they meet and overlap, as 
in Fig. 30, and hammer them, at a red heat, now 
on the face of the anvil and now on the horn, till 
they fit together closely. You are now ready for 
the welding. 

For this make sure, as in the last exercise, that 
you ha\'e a hot fire of good coals, and get a thor- 



UP8ETTINQ AND WELDING. 



39 



ough good welding heat, without burning. There 
is special danger of burning in exercises like this, 
in which the piece is small, and has a thin edge. 




Fig. 29. 



As soon as it shows, by the vivid sparks which it 
emits, and by its intense whiteness when viewed 
through the chinks in the fire, that the proper 
heat has been reached, place it as quickly as pos- 
sible on t\\e anvil, and hammer the parts together 
by quick light blows. AVhen they have adhered. 



} — %: 



Fig. 30. 



the extra metal produced by the upsetting and 
scarfing may be hammered down on the horn of 
the anvil, and the link brought to its proper shape, 
more at your leisure and at a lower heat, 



40 FIRST LESSONS IN METAL-WORKING. 

In this exercise, and in general in all welding 
operations, it is necessary that the surfaces of con- 
tact should be quite clean, or if there is anything 
on them, it should only be something fusible, 
which will squeeze out under the blows of the 
hammer. Coal-dust will generally burn off and 
not give much trouble. Cinders, if your fire 
should be so " dirty " as to allow any to settle on 
the joint, which ought not to happen, can often 
be shaken off by a sharp blow on the edge of the 
anvil. The oxide of iron also, in the intense heat 
of the welding fire, is generally driven off as fast as 
it is formed. But Avhile the piece is exposed to the 
air on the anvil, and on its way there, some oxide of 
iron is formed which is not got rid of, but which 
falls off under the blows of the hammer, and is 
found on the anvil as black scales. If any of this 
forms on the surfaces of contact, or if any cinder 
is held between these surfaces during the weld- 
ing, the iron will not adhere well, and the weld 
will fail. This therefore is another reason Avhy 
you should work quickly at this stage. 

This oxide of iron, when its formation cannot 
be prevented, is removed by the use of white sand 
or borax as a ^^ flux," that is, a substance which 
unites with the oxide and makes a sort of glass, 
which is fusible and is squeezed out by the ham- 
mer. With good wrought-iron the flux is not 
generally necessary, provided a true welding heat 



UPSETTING AND WELDING. 41 

is used and tlie work is done quickly. With 
steel, as will be seen hereafter, it is indispensable. 
When a flux is used with wrought-iron, it is to be 
sprinkled on the joint, or the iron is to be plunged 
in the flux, but only at the welding heat. At a 
lower temperature the sand will not adhere and 
melt, and will do no good. At the welding heat 
it melts and spreads over the surface, partially 
protecting it from the air, and allow^ing it to be 
raised to a higher temperature without burning 
so much. When it is put into the fire again, the 
brilliant white s]3arks still appear, and as it is 
carried to the anvil it will give forth a hissing 
noise. When this happens you are pretty sure of 
a good weld if you work quickly. 

The form of the joint is important also, with 



L^_SZ=A' 



\ 




T 




Fig. 31. 



reference to the escape of impurities. If the sur- 
faces of the scarf are concave, as in Fig. 31, a, 



42 FIRST LESSONS IN METAL- WORKING. 

the welding takes effect first at the two points of 
contact shown, and some of the impurities may be 
imprisoned, and prevent a good union of the pieces, 
though in general they will escape sideways, par- 
ticularly if the surfaces are small. If the surfaces 
are convex, as at b, they touch at first only at 
the middle, and there is sure to be plenty of op- 
portunity for the impurities to escape, however 
large the surfaces may be. The same result is 
secured nearly as well if the surfaces at a are put 
too-ether in the manner shown at c. 

It is desirable that the weld should be accom- 
plished at a single heat, because in reheating the 
danger of burning is increased ; but you must not, 
merely to avoid this risk, allow an imperfect weld 
to pass. 

Inspect your work critically when done. It 
should show the following appearances : 

1. The weld should be invisible. 

2. The iron should not be burned away at the 
thin edges of the scarf, leaving little notches ; yet 
this is a less serious fault than if the scarf itself is 
visible as a fine crack for the whole or a part of 
its length. 

3. The ring should not be any thicker at the 
weld than elsewhere, nor any thinner, — which is 
more likely to happen, and is a more serious fault. 

4. The iron should be of circular cross-section 
throughout, and without bruises, 



UPSETTmQ AND WELDING. 



43 



5. The link should be a perfect ellipse, and 
with the 7-iiich piece of ii'on that yon have used, 
should be of the exact size and shape of Fig. 32. 




Fig. 32. (Full size.) 

If the iron is too much reduced, or the weld 
bad, cut out the imperfect part, and rej)eat. This 
will, of course, make the link too small. After- 
wards, take a new piece, and try again. 

The scarfed surfaces in this exercise may be 
prepared in another way, using the face of the 




Fig. 



hammer instead of the pene. Having upset and 
bent the piece as before, lay it on the anvil as in 
Fig. 33, only about half an inch of the ends rest- 



44 FIBST LESSONS IN METAL WORKING. 

ing on the anvil. With a full red heat, strike a 
blow or two on one end, holding the face of the 
hammer parallel to that of the anvil. Draw the 
piece toward you about -^-^" and strike again. 
Kepeat this operation out to the end of the piece, 
then turn it over and treat the other end the same 
way. The edge of the anvil thus serves the same 
purpose as the pene of the hammer in the pre- 
vious method. In this ease also, as before, the 
piece must be lightly hammered on the sides to 
partially correct the spreading. 



BLACKSMITH. AND HELPER. 45 



LESSON VIII. 

BLACKSMITH AND HELPER. 

You will now join two separate pieces by a 
scarf-joiut. In this case, botli pieces, when pre- 
pared and heated, will have to be held in tongs 
to bring them together. If one workman attempts 
to do this, he has to lay down one pair of tongs 
and take np his hammer, and thus runs the risk 
of having one piece fall out of its place, or both 
pieces get chilled. The ojjeration is therefore 
much more easily performed with the aid of a 
"helper," who follows the lead of the other work- 
man, called the '' blacksmith " or ''fireman," strik- 
ing and stopping as the latter directs, and work- 
ing the bellows while the other manages the fire. 
A skilful workman can indeed perform this task 
without a helper, particularly with the aid of cer- 
tain devices to be described presently; but many 
other operations, particularly on heavy pieces, are 
impossible without a helper. 

Cut two pieces of 1'' square iron, each b" long. 
If you fail to do this exactly, make a memoran- 
dum of the exact amount of your error, that you 
may, when the work is finished, learn how much 
has been used up in the weld, and therefoi'e be 



46 FIRST LE8S0N8 IN METAL- WORKING. 

able to make the proper allowance for such a joint 
in the future. 

Place both pieces with one end in the fire, but 
bring only one at a time to a white heat. Hav- 
ing the services of a helper, we will 
Exercise 16. ^|^-g ^-^^ prepare the scarf with the 

Use of fuller. ^ -■- 

tool called a " top-fuller." This is a 
tool very much like the pene of your hammer, the 
edge being set (as may also be the case with the 
hammer) either parallel or perpendicular to the 
handle. It is held in one hand by the blacksmith, 
and struck with a heavy hammer, or " sledge," by 
the helper, w^hile it rests on the part of the piece 
which is to be indented. As an unskilful blow 
may give a painful Jar to the hand of the holder, 
the handle of this or any similar tool is sometimes 
made of twisted wire, or even of a withe or rod 
of hazel or other flexible wood. The rod is sev- 
eral times wetted, heated, and twisted at the mid- 
dle, to loosen the fibres of which it is composed. 
It is then passed once or twice round the head of 
the tool, twisted, and held in place by a small iron 
ring, as in Fig. 34. With this flexible handle the 
hand of the holder is safe from shocks. A similar 
tool, with the edge turned upward and shaped like 
the hardee, so as to be set in the anvil, is called a 
"bottom-fuller." 

To make the scarf-Joint with this tool, the fire- 
man brings the end of the piece to a white heat, 



BLACKSMITH AND IlELPEK. 47 

as before, and bevels and upsets it, as in Figs. 24 
and 26. Then, taking the fuller in the right 




Fig. 34. Fig. 35. 

hand, he holds it on the bevelled surface, as in 
Fig. 35, while the helper strikes it with the sledge. 
It is easy to see that this tool can be guided with 
more accuracy than the pene of the hammer. 
With this the two pieces are brought to the form 
shown in Fig. 31 B. They are then laid in the 
fire, the scarfed surfaces downward, that no dirt 
may fall on them as they are removed from the 
fire, and as close together as they can be placed 
without touching, in order that they may arrive at 
the welding heat at the same time. They must not 
touch, however, as they would adhere in the fire. 
When they have been sprinkled with 

•^ ■•■ . Exercise 17. 

sand and brought to the full weldmg scarf-joint 
heat, they are taken quickly from the ^^^'^ ^'^^ 
fire, first one piece by the helper and 
then the other by the blacksmith. The helper 



48 FIRST LE880N8 IN MEIAL- WORKING. 

goes first, because his place is on the farther side 
of the anvil, while the blacksmith stands between 
the anvil and the fire. The helper strikes with 
his piece a sharp blow on the edge of the anvil 
farthest from him, to knock off any cinders that 
may be on it, and then rests it on the near edge, as 
in Fig. 36, the scarf surface up, but being very 




Fig. 36. 

careful not to let the thin edge of the iron touch 
the anvil, which would chill it. The blacksmith 
follows quickly with his piece, knocking off dirt 
in the same way, and places it on the first piece, 
as in Pig. 37. It is of the utmost importance that 




Fig. 37. 

the first piece be neld quite steady, and the second 
placed on it in exactly the right position. If it 
laps a little too much or not quite enough, the 
scarf will turn out bad. The thin edges, which 



BLACKSMITH AND HELPER. 



49 



may have cooled a little in the air, are lieated again 
by contact with the tliicker parts. A quick light 
blow or two at h by the blacksmith, will make the 
iron adhere. The blacksmith turns the piece over 
and makes it adhere at a in the same way. It is 
then laid flat on the anvil, as in Fig. 38, and welded, 




Fig. 38. 

with heavier blows, by blacksmith and helper 
together, the former with his hammer, the latter 
with a sledge. The blacksmith strikes wherever 
he considers it best, and turns the piece when 
necessary, and the helper follows him, striking at 
the same point, and beginning and stopping when 
the blow of the blacksmith's hammer on the piece 
or on the anvil gives the signal. Test the weld 
before finishing. Holding one end of the piece 
with the tongs, strike it at the middle, while hot, 
over the horn of the anvil, bending it, and then 
again straightening it or bending it the opposite 
way. The weld should not open under such treat- 
ment. If the weld is satisfactory, the piece is fin- 
ished smooth and square with the "flatter," Fig. 
89, which is held on tlie bar by the blacksmith and 
struck by the helper. With this tool, of course, 



50 



FIRST LE880N8 IN METAL-WORKING. 



a better finish is possible tlian with the hammer 
Exercise 18. ^loue. The bar should be tested at 
Use of the the weld with calipers and square, 
flatter. ^^^ made perfectly straight. After 

this it may be finished smooth and partially pol- 
ished, by dipping the face of tlie flatter in water 




Fig. 39. 

and slightly wetting with it the face of the anvil 
during the last part of the hammering. 
The result of the work should be — 

1°. A perfectly straight bar; 

2°. Of uniform cross-section of 1" ] 

3°. Perfectly square ; 

4°. Without any twist ; 

5°. With no visible or a scarcely visible weld ; 

6°. Nowhere burnt; 

7°. Quite smooth and polished; and, 

8°. Exactly 11^' long. 

If its length differs from that given, it is be- 



BLACKSMITH AND HELPER 51 

cause you did not cut tlie pieces to the right 
length, or because you have used up too much 
material in welding. In either case note the 
facts in your memoranda, and be forewarned for 
the next task of the kind. 



52 FIRST LE8B0N8 IN METAL- WORKING. 



LESSON IX. 

WELDINa (continued). A TONGUE- WELD. 

The scarf- weld just practised is an excellent 
joint, and, for most purposes, as good as can be 
desired. For many heavy pieces, such as shafts 
of steamers, the tongue- joint, Fig. 40, is often 



I 



Fig. 40. 

used, and even in smaller work, such as the re- 
pairing of a broken wagon-axle, it is useful. 
Moreover, it can be more easily managed without 
the aid of a helper than the scarf -joint can. We 
will exemplify it with pieces of the same size as 
those used in the last exercise. Cut them, as be- 
fore, to the exact length, or record the error. 

Heat the pieces, and hammer one of them out 
on the edge of the anvil, to the wedge-form. Fig. 
41, A. The hammering will " spread " or widen 
the piece on the edge, as shown in the plan b. 
This widening is to be, for the present, only very 
slightly reduced, by hammering on the sides. 

Upset the other piece as in the last exercise, 



WELDING. A TONOVE-WELD. 



53 



o-iving it the appearance shown in Fig. 42, a. 
This piece is now to be split and opened, as 



> 



■I 




Fig. 41. 



Fig. 42. 



shown in Fig. 42, b, to a depth equal to the 
len^Hh of the wedsire. It is important that the 
opening should be of this depth, otherwise a 





Fig. 43. Fig. 44. 

portion of the reduced thickness of the wedge 
will be left exposed, and the piece, when finished, 



54 



FIRST LES80N6 IN METAL- WORKING. 



will be too small at this point. If, on the other 
hand, the cut is too deep, the wedge will go in too 
far, and the piece will be shortened, besides being 
thickened at the joint. The slit is made with a 
"hot chisel," Fig. 43, that is, a chisel adapted to 
the cutting of hot iron. While the piece is at a 
bright red or white heat, the blacksmith holds it 
on the edge of the anvil, as in Fig. 44, and holds 
the chisel on the line of the proposed cut, and the 
helper drives the chisel in with blows of the 
sledge. The workman does not try to make the 
whole length of the cut at once, but begins at the 
end, and works gradually inward. When the cut 
is about half-way through, he turns the piece over 




Fig, 45. 

and w^orks from the other side. The cut being 
Exercise 19 made, it may be widened by setting 
A split or the piece on end, with the cleft up, 
v-weid. .^^^1 driving the chisel into it, or by 

setting it up with the cleft down, and driving it 



WELDING. A TONGUE-WELD. 



m 



on the hardee, or on a bottom-fuller. When the 
piece has been split, hammer out the edges of the 
Jaws a little, as in Fig. 45, thinning them only a 
little, and then close the jaws again, partly, as in 
Fig. 46. If you have no helper, the whole opera- 




FiG. 46. 

tion may be performed, though not quite so easily, 
on the hardee and a bottom-fuller, or even by 
holding the piece in the vise, and splitting it with 
a chisel. 

The split piece, or V-piece, being now again 
heated to whiteness, the blacksmith holds it up- 
right on the anvil with one pair of tongs, and the 
cold wedge-piece with another pair, while the 
helper drives it in gently. The wedge must enter 
to its full depth, and, if necessary, the cut must 
be extended for this purpose, for the reason al- 
ready given. It must also go cpiite to the bottom 
of the cut, otherwise a hole will be left in the 
finished piece at that j^oint. 

The wedge being quickly di'iven in to its proper 



56 



FIRST LES80N8 IN METAL-WORKING. 



de]3tn, tlie pieces are turned over on their side, 
and the jaws of the slit hammered down closely 
on the wedge, the blacksmith and helper push- 
ing the pieces firmly together all the time, to pre- 
vent the wedge from slipping out. The ears a 
and h, Fig. 47, b, which project beyond the edges 




i- 



Fig. 47. 

of the wedge-piece, are to be turned down round 
it, thus holding the two pieces together while the 
weld is being finished. The two pieces thus 
joined together are laid in the lire and brought 
to a welding heat. Two or three blows struck 
lengthways will make the w^eld secure at the 
middle. Then reheat, and, blacksmith and helper 
together pushing strongly towards each other, fin- 
ish the weld while the piece lies on its side and is 
turned to and fro by the former. 

The finishing is effected in the same way as in 
the last exercise, and the same tests are applied to 
the work. 



WELDING. A TONOUE-WELD. 57 

This joint can be made by one workman alone, 
if lie is skilful and tlie pieces are not too large. 
He will cut the slit on the hardee, or in the vise 
with a chisel. To diive the cold wedge into the 
V , he will hold the V -piece, red-hot, upright in 
the vise, and holding the cold wedge-piece in the 
hand, drive it in with the hammer. He will then 
squeeze the jaws of the V together with the 
tongs, and turn the ears over the wedge by light 
blows of the hammer on the anvil. The two 
pieces should then hold together iirmly enough to 
allow of handling them (with care) in the fire, 
while being heated for the weld. 

The V-weld, or split-weld, is especially valua- 
ble for very large pieces. With such pieces, after 
the joint has been formed and the two pieces have 
been fitted together, and while they are at a ^veld- 
ing heat in the fire, they are partly welded, with- 
out removing them from the fire, by blows of a 
heavy sledge on the end. Only the finishing of 
the weld has then to be done on the anvil. 



58 FIRST LES80N8 IN METAL-WORKING. 



LESSON X. 

TESTIIN'G IPvON. MAIN^UFACTUKE OF CAST-IRON. 

Baes welded by any of these methods should be 
almost as strong as bars without welds. They can 
be readily tested in a machine such as that used 
in the Lessons on Wood-working, only larger and 
stronger. Such machines are made of sufficient 
power to break a bar of wrought-iron five inches 
in diameter. The small machine wnll serve for 
testing wires, and such pieces as were used in 
your first exercises ; and you should now make a 
few welds with such iron and test them, compar- 
ing their strength with that of the solid bar. 

Put one of these pieces, \" square, into the ma- 
chine, and apjDly a gradually increasing force till 
the piece breaks. The cross-section being yig of a 
Exercise 20. square iuch, the '' tensile strength" 
Testing bars or " tenacity" of the iron per square 
and welds. -^^^-j^ -^ gj^teeu timcs the amount that 

the testing-machine indicates. If the bar were 
round and \" in diameter its cross-section would 
be about -^-^" (-eVoVO? ^^^^ ^^^ tenacity about 20 
times that of the specimen. This strength varies, 



TESTING IRON. MANUFACTURE OF CAST-IRON 59 

for different kinds of wrougLt-iron, from 35,000 
to 55,000 lbs. It is usually higher for iron wire 
than for bar-iron, because none but the best qual- 
ity of iron can be used for making wire, and be- 
sides, the " drawing" of the wire lengthens and 
compresses the fibres, thus giving additional 
strength. Test two or three specimens of wire, 
and calculate their tensile strength. 

The tensile strength of wa'ought-iron is not 
the only important quality that can be tried and 
measured in the testing-machine. Good wrought- 
iron should have great ductility, that is, it should 
suffer considerable stretching, and consequently 
considerable reduction of cross-section, before 
breaking. If it does not, it is not fit for use in 
such a structure, for instance, as an iron bridge, 
because when a great stress is put upon it, in- 
stead of stretching, and so giving warning, it will 
break suddenly. It is usual, therefore, with en- 
gineers to require that the iron to be used in 
bridges, shall suffer an elongation of 12 to 20 per 
cent and a reduction of cross-section Exercise 21 
of 30 per cent before breaking. Mea- Test of 
sure the diameter of the section of the '^"^^^^^^y- 
broken rod at the point of rupture, compute its 
area, and the percentage of reduction. 

Besides tenacity and ductility, good wrought- 
iron has great hardness and stiffness, that is, it re- 
quires great force to crush it or to bend it. Test 



60 FIRST LESSONS IN METAL-WORKINO. 

a specimen of \'' wi'ouglit-iron in tliese respects in 
the macliiue, and record the results for compari- 
son hereafter with cast-iron and with steel. You 
will find that w^hile different kinds of wroiight- 
iron differ from each other, they are, on the aver- 
age, superior in all these respects to cast-iron. 

The differences between cast-iron, wrought-iroD, 
and steel, and between different specimens of 
each, result from their composition and mode of 
manufacture. Cast-iron is a mixture of iron with 
about 4 to 7 per cent of carbon, which makes it 
fusible at about 1100° C. or about 2500° F. It 
generally contains also, small quantities of othei* 
substances, as sulphur, silicon, and phosphorus, 
which have various effects on its fusibility, its 
ductility, and its hardness. As more and more 
of the carbon is removed, the iron becomes first 
steel and then wrought-iron, endless varieties of 
each resulting from the kind and quantity of the 
impurities. The way in which these substances 
find their way into the product, and the means by 
which they are removed, will be understood from 
a brief description of the methods of manufactur- 
ing cast-iron, wrought-iron, and steel. 

The broken-up ore is placed in a structure forty 
to eighty feet high, called a ^'blast-furnace," shown 
in Fig. 48, in layers alternating with layers of 
coal or charcoal and of broken limestone. The 
coal beino; is^nited and a strong; blast of air driven 



TESTING IRON. MANUFACTURE OF CAST-IRON. 61 



through the iron pipes or " tuyeres" which enter 
the furnace near the bot- 
tom, the heat melts the 
material above, which 
flows off below through 
the opening shown in the 
iigure. Fresh layei's are 
added above, and thus the 
furnace is kept in con- 
stant action, for months 
or years, till it becomes 
necessary to let the fire 
out in order to make re- 
pairs. 

The use of the coal in 
this operation is evident. 
That of the limestone is 
to form an easily fusible 
mixture with the silica or 
sand and the earthy mat- 
ter of the ore, and cause it 
to flow off. At the same 
lime some of the carbon of 
the fuel joins with the iron 
and makes another fusible 
mixture, cast-iron. There 
are thus two fluids con- 
stantly accumulating in 
the bottom of the furnace. The heavier one settles 




Fig. 48 



62 



FIRST LESSONS IN METAL- WORKING. 



to the bottom, and is drawn off from time to 
time, tlirough an opening made for the purpose, as 
cast-iron. The lighter one floats above this, and 
is drawn off through another opening, as "slag" or 
" cinder." When cold, it is usually, though not 
always, broken up and thrown away as a waste 
product. 

The iron thus obtained from the furnace flows 
down a trough ^4^ in a bed of sand on the floor 
to the troughs i>^, and thence into the moulds 




CO. One of the groups composed of ^ and O is 
called a " sow and pigs," and the pieces O, each 
of which is about three feet loni>; and contains 
about 100 lbs. of iron, is called a "pig." 

The " pig-iron" thus produced contains various 
impurities, according to the hinds of ore, lime, and 
fuel used. The study of the various grades of 
pig-iron would lead us farther than we can go at 
present. They are designated, in part, by tlie 
name of the country or district in which they are 



TESTING lEON. MANUFACTURE OF CAST-IRON 63 

produced, or the furnace producing tliem — Norway, 
Cumberland, Lownioor, Warwick, Salisbury. Be- 
sides this, they are also divided into three princi- 
pal grades used for different purposes. These 
are : 

^^ No. 1," which is coarsegrained and very dark 
and soft, and is used for foundry-work ; 

" No. 2," which is less coarse, but still dark and 
soft, and is also used for foundry- work ; 

" No. 3," or Gray Forge, also sometimes called 
No. 1 Mill ; 

'' Mottled j'' \n\\\q\i is light gray with specks of 
white ; and, 

'• White j^ which is white all over. 

The last three are used for reheating and manu- 
facturing into refined iron, as explained in Lesson 
NIL 



64 



FIBST LESSONS IN METAL- WOBKINO. 



LESSON XL 



^OUI^^DRY-WORK. 



Cast-iro]^ is readily fusible, and a great many 
articles are made directly from it in the ^4i*on-foiin- 
dry," different kinds of pig being mixed together 
to obtain the desired quality. To illustrate the 
method of casting or founding in metal, which is 
Exercise 22 ^^^^ Same in its essentials, whether the 
Making a metal be iron, steel, brass, or zinc, we 
pattern. ^^^l cast a Small object in brass, which 

can be melted in your forge-iire or in that of a 
small portable furnace, while iron would require 
a much higher temperature. We will take for 
the object the square prism shown in isometric 
projection in the sketch, Fig. 50, to 
be used in a later exercise. The rough 
casting must be a little larger than it 
is shown in the sketch, to allow for 
waste in finishing. The amount of 
the difference depends on the fine- 
FiG. 50. ness of the casting. If the casting 
is very rough, ^'^ may be lost on each face; 




FO UNDR Y- WORK. (55 

if very smootli, less than yig^' maybe euough. As 
we shall perform several operations on tlie casting 
before iinisliing it, we will make the casting 2J'' 
square and 2^^' long. If, however, we make a 
mould of this size, the metal when poured into it 
will shrink in cooling, and make the piece too 
small. It is usual, as the result of experience, to 
allow about 1 per cent or about ^" to a foot for 
shrinkage ; but this allowance, which is important 
in large pieces, may be neglected in so small a 
work as the present. 

If the pattern were made of the size and shape 
thus far determined on, 3^ou would find, on trying; 
to perform the next operation, that you w^ould 
fail. After packing the sand round your pattern 
in the mould, you would find that the pattern 
would not •' draw," that is, it could not be lifted 
from the sand without breaking^ down the mould 
It must be a little thinner on that side which is 
set deepest in the sand. The least taper that will 
suffice for this purpose is about ^^ in a foot, or 
about y-^o"'' in an inch. Allowing something more 
than this in this very small piece, you may make 
one face of your pattern about ^'' wider than the 
opposite face. Finish up the pattei'n as smooth 
as you can make it, and give it a smooth coat of 
shellac varnish. 

The process of " moulding" consists in making 
a depression in sand, of the size and shape of the 



66 



FIRST LE880N8 IN METAL- WORKING. 



pattern, and that of ^' casting" consists in filling 
this depression with the melted metal. The sand 
must be very firm, and jnst moist enough to 
" pack," or stick together slightly when squeezed 
in the hand. If it is moister than this, it may 
cause accidents by the sudden generation of steam 
when the melted metal is poured into the mould. 
The sand is held in place while it is being packed 
round the pattern, by a moulding-box or " flask," 
of wood or iron, formed in two parts, which can be 
separated and put together again in exactly the 
same position, being guided by two pins in one 
part, which pass through two holes in correspond- 




3 c 



3c 



Fig. 51. 






3 C 



ing ^'lugs" on the other. Each part is accom- 
panied by a flat " moulding-board " about two 
inches longer and wider than the flask, with 
" tongue-and-grooved " strips across the ends to 



FO UNDR Y- WORK, 67 

prevent it from warping. The two parts A and B^ 
with the moulding-boards C\ are shown in front 
elevation and side elevation in Fig. 51, wdiere P 
and Q are the upper and lower lugs. 

Set one half of the flask on its monlding-board, 
with the lugs downward. Sprinkle 
some fine sand on the lower part of the fL^®^"?.^^ ^^' 

^ Moulding. 

flask, through a sieve, and fill up the 
remainder of the box without sifting, bnt press 
and ram the sand firmly into the corners of the 
box till it is quite full. Scrape off the excess with 
a straight-edge, sprinkle a little loose sand on the 
surface, and cover it w4th another board, rubbing 
this to and fro till it fits closely on the edges of 
the box. Now, grasping the edges of both boards 
in the hands, turn the box over without disturb- 
ing the sand, and remove the upper board. 
Sprinkle the moist surface of the sand with fine 
red brick-dust obtained by crushing bricks. Put 
the dust into a linen bag, and sift it out by sha- 
king the bag while holding one corner of the open 
end in one hand and a corner of the bottom in the 
other. Blow off any excess of dust, and lay the 
pattern on the sand with the wider face dowai. 
Sprinkle the surface of the pattern with dust, then 
set the upper part of the flask in place, and fill it, 
and cov.er it with a board in the same way as the 
first. 

The upper half is now to be removed, so tliat 



68 FIRST LESSONS IN METAL- WORKING. 

the pattern may be taken out. Tap tTie top board 
gently all over with a light mallet. This will 
loosen the sand a little from the pattern, and the 
brick-dust will prevent the two surfaces of the 
sand f]'om sticking together. Taking hold of the 
upper box and moulding-board with both hands 
and lifting carefully straight upwards, you can 
remove this box and turn it over on its moulding- 
board. In lifting, you must be careful to keep 
the box quite level and not to move it horizontal- 
ly, or you will break the mould. 

If the sand has not broken away to any consid- 
erable extent, you may remove the pattern ; but 
if it has, the breaks must first be repaired. 
Moisten a little the hollows from which the sand 
has been torn out, and replace the other box. 
The pieces torn out will adhere and remain in 
their proper places, where they can afterwards be 
smoothed off, if necessary, with a small trowel. 
If the pattern should happen to come oif with the 
upper flask, it can be removed by sticking into it, 
obliquely, two sharp-pointed steel wires, tapping 
them gently sideways and endways to loosen the 
pattern, and then lifting it out by the wires as 
handles. 

In one end of the flask there is a hole through 
which the melted metal is to be poured in. Con- 
nect this with the end of the mould by a small 
channel cut with the trowel, and smoothed and 



FOUNDRY-WORK. 69 

liardeiied at the entrance by the pressure ot the 
finger. Repair any small breaks, \Ao\y out any 
loose sand, dust both surfaces of the mould lightly 
with flour or with finely ]>owdered charcoal in the 
same way that you applied the brick-dust, put the 
two halves of the flask together and clamp them 
in place, and everything is then ready for the 
pouring of the metal. 

Brass is best melted in a brass-founder's furnace, 
which, however, it is not necessary to describe 
here, as the small quantity required at present can 
be melted in a crucible in your forge. Make a 
Are of good hard coke, in pieces about t^vo or 
three inches in diameter. Set the crucible on this, 
mouth downwards, urging the fire gently till it is 
thoroughly heated, because, if heated first on the 
outside, or too suddenly, it is apt to crack. When 
it is red hot all over, turn it over, build up the 
fire round it to the edge, put in the charge of 
metal, and cover it with large pieces of coke. 
The amount of metal required can be determined 
approximately f]-om the fact that the density of 
the metal is 14 or 15 times that of the wooden 
pattern. To allow for waste, however, and to be 
quite sure of having enough to fill the mould, let 
the weight of the charge be from 20 to 25 times 
that of the pattern. Keep up a strong draught 
with the bellows, till the whole of the charge is 
melted. 



70 FIRST LES80N8 IN METAL-WOBKING. 

Brass is an alloy or mixture of copper and zinc, 
usually in the ratio of 90 to 10. When it is ex- 
exposed to the air at a very high temperature, the 
zinc burns, giving off a light blue flame and a 
cloud of white smoke. For thin castings, which 
chill quickly, and which therefore require a high 
temperature, the metal should be poured in this 
condition. For such a piece as the one in this 
exercise, a somewhat lower temperature will be 
best^ such as is unattended by the flame and smoke. 
When the metal has cooled to this point, skim off 
the dross, and it is then ready to be poured. 

For this purpose, after having turned the flask 
downward to let any loose sand that might pos- 
sibly have falleD into the mould fall 
Exercise 24. ^^x ^^^ j^ upri2:ht, with the mouth 

Casting brass. ^ ^ 

Up, and m such a way that the point 
of the mould at which the inlet enters shall be the 
highest point, otherwise the air will collect at any 
point that may be higher, and prevent the metal 
from entering. Pour the metal carefully into the 
mould, in a steady stream of such size as to leave 
room in the channel or " ingate" for the escape of 
the air without forming bubbles, which might 
scatter the metal. The mould must be filled quite 
up to the ingate, to insure soundness of the cast- 
ing at the top. When the casting is " set," the 
mould is opened, the piece cooled, the ingate-piece 
sawn oft*, and the ridge along the line of meeting 
of the halves of the flask filed away. 



MANUFACTURE OF WROUOHT-IKOK. 71 



LESSON XII. 

MANUFACTUEE AND PEOPERTIES OF WROUGHT-IRON. 

We have seen that the two kinds of iron, 
called No. 1 and No. 2 foundry pig, are used 
singly or mixed in various proportions for cast- 
iron, and No. 3, or forge-pig, is manufactured into 
wrouo-ht-iron. The manufacture consists in ex- 
pelling the other substances, mainly carbon, sili- 
con, phosphorus, and sulphur, with which it is 
mixed, leaving pure iron. 

For this purpose, the iron is again melted in a 
furnace without blast, called a " puddling-furnace," 
where it is stirred up with wrought-iron rods till 
nearly all the carbon has been burned out of it 
by contact with the air, and the other impurities 
have been carried away in a "slag," made by 
throwing limestone, oxide of iron, salt, and other 
fusible substances into the furnace. It thus be- 
comes first pasty and then granular, and requires 
a very intense heat to keep it from solidifying. 
In this state it is taken out of the furnace in 
lumps of about 40 lbs., on the ends of the iron 
rods, and hammered by heavy hammers driven 
l^y machinery, or compressed between powerful 
'' squeezers," the remaining silicon and other im- 



T2 



FIRST LESSONS IN METAL WORKING. 



purities being thus pressed out. The lump of 
pure iron thus obtained is passed between strong 
cylindrical rollers, which have grooves turned in 




Fig. 52, A. 

both, opposite each other as in Fig. 52, and thus 
drawn out into bars from 3 to 5 inches wide, and 




Fig. 52, B. 

from ^" to ^" thick. These are called "muck- 
bars," or '^ puddled bars," and are coarse WTought- 
iron. These bars are cut into short pieces, which 
are fastened together, reheated, and again rolled 
out to such sizes and shapes as may be required. 



MANUFACTURE OF WROUGHT- IRON. 73 

The irou thus produced is called " refined " iron. 
This iron is sometimes again "piled" and reheated 
and rolled, producing what is called "double re- 
fined" iron. After these operations the iron will 
be found to have an entirely different structure 
from that of cast-iron. The latter is composed of 
granules or crystals. Wrought-iron, if good, has 
lost its granular or crystalline structure, each of 
the granules having been drawn out into a long 
fibre, so that the bar itself is a bundle of such 
fibres stuck tosrether at their sides. Wrouo-ht- 
iron thus resembles a piece of tough wood, while 
cast-iron is more like unstratified stone, such as 
granite. Cast-iron has the same structure and 
strength in all directions, while wrought-iron is 
tougher or harder to tear asunder by a force ap- 
plied in the direction of the length of the fibres 
than by one applied perpendicular to this direc- 
tion, — in which respect again it is analogous to 
wood. (Wood- working, p. 17.) 

This fibrous structure is possessed in very differ- 
ent degrees by different kinds of wrought-iron. An 
iron of poor quality can be readily broken across 
by bending. Take a piece of \" bar-iron of the 
cheaper (and therefore poorer) quality. 
Nick it on one side on the hardee. Testing 
Lay it across two pieces of ^" flat wrought-iron 

,1 _e • 1 J i 1 on the anvil. 

n-on tnree or tour inches apart on the 

anvil, the nick being between the supports, but 



74 FIRST LESSON'S IN METAL- WORKING. 

near one of tliem, and strike it a heavy blow or 
two with the pene of a hammer. If the specimen 
is of very poor quality, or " cold short," it will 
break at the nick. A piece of better quality 
will stand bending cold at right angles without 
breaking; and a very tough piece may be bent 

^ double without breaking:, or 

will split at the nick, as m 

Fig. 53. The best bar-iron 

\ can be tied in a knot cold, 

^ though not after it has been 

^^^- ^^' nicked. 

Break in this way two or three pieces of iron 
of different qualities. Examine the surfaces of 
the fractures with a lens. You find that the bet- 
ter or tougher the iron, the more distinctly fibrous 
it is; and you can soon learn to judge of the 
quality of wrought-iron, as of cast-iron, by the 
appearance of a freshly-broken surface. 




MANUFACTURE AND PROPERTIES OF STEEL. 75 



LESSON XIII. 

MA^UFACTUEE AND PROPERTIES OF STEEL. 

You have learned that wroiigbt-iron is Dearly 
or quite pure iron, while cast-iron contains from 
3 to 5, or, in some cases, even 7 or 8 per cent of 
carbon. Steel is intermediate in composition be- 
tween these two, and contains from 1 per cent to 
0.15 of one per cent of carbon. It might be sup- 
posed, therefore, that steel could be made in the 
puddling-furnace by stopping the operation be- 
fore the carbon is all removed ; and this process is 
sometimes actually used. It is difficult, however, 
to obtain in this way a product containing exactly 
any desired proportion of carbon, and besides, the 
distribution of the carbon throughout the mass is 
apt to be irregular, or, in other words, the steel is 
not homogeneous. 

For a long while, therefore, steel was made al- 
most exclusively from the best qualities of 
wrought-iron l:>y a process called ^'cementation," 
a process which is still in use for the manufacture 
of fine steel. The bars of wrought-iron are em- 



76 FIRST LESSONS IN METAL- WORKING. 

bedded in powdered charcoal, and baked in a 
furnace for from seven to fourteen days continu- 
ously. Tlie iron is then found to have increased 
in weight about 1^ per cent by the absorption of 
carbon, and has become what is called "blistered" 
steel, from the blisters which appear on its sur- 
face, and which are probably caused by the escape 
of bubbles of air. 

From the blistered steel two other kinds are 
made called "shear" steel, and "cast" or "cruci- 
ble" steel. The former is made by fastening to- 
gether a number of bars of blistered steel, and 
hammering them at a welding heat with a trip- 
hammer. The process is like that of refining 
wrought-iron, and has a similar eifect — the pro- 
duction of a more or less fibrous structure. The 
steel thus made is especially adapted for welding 
to wrought-iron, and is commonly used in making 
the cutting edges of those tools of which the 
other parts are made of iron. The other kind of 
steel is made by melting in crucibles bars of blis- 
tered steel, broken for the purpose into conven- 
ient fragments. This is harder to weld than 
shear-steel, and is used principally for objects 
which are entirely of steel, and which are cast in 
the shape required, although it can also be 
welded, with proper precautions. 

As long as steel was manufactured only by the 
methods just described, only a small cpantity 



MANUFACTURE AND PROPERTIES OF STEEL. 11 

could be produced at once, and it was therefore 
very expensive. When large works are to be 
made of crucible steel, it is necessary to have 
great numbers of crucibles ready at the same time 
for pouring, and very great care is necessary to 
make sure that the charo-es of all the crucibles 
shall have exactly the same qualities. With such 
precautions, however, very large works, such even 
as cannons weighing 139 tons, are satisfactorily 
cast at the great Krupp foundry in Germany. 

In recent times much less expensive processes 
have been devised for making steel in very large 
quantities. These are known as the Bessemer 
process and the Siemens-Martin process. They 
need not be described at present. They are used 
mainly in the production of very large pieces, such 
as are used in the construction of heavy machinery, 
bridges, railroad tracks, steel ships and cannon, 
and the armor-plating of war-vessels. For small 
tools, shear-steel and crucible-steel are still gener- 
ally employed. 

To the mechanic who is working in steel, the 
properties of the metal are generally more impor- 
tant than the way in which it may have been 
manufactured ; and in wdiatever way his steel may 
have been made, he distins^uishes what he calls 
"high-grade" or '^tool" steel from "low-grade," 
" mild," or " machinery" steel. The former con- 



78 FIR8T LESSONS IN METAL- WORKING. 

tains about 1 per cent of carbon, tlie latter from 
J- to -^ as much. 

On your anvil are two specimens of \'' square 
steel, each 18^^ long. One is of high grade, the 
other of mild steel. Study the properties of each. 
First, heating them to redness, nick them both on 
the hardee, 8[^_ from the end; and then, after cool- 
ing them slowly, try to break them as you did 

Exercise 26 ^^^ ^^'^^^ ^^ Excrcise 26. Or better. 
Testing steel lay the piecc across the hole in your 
on the anvil. 2inN'A, hold a uarrow fuller on the nick, 
and let a helper strike with a sledge till the piece 
breaks. Compare the effort necessary to break 
each of these with that required to break a piece 
of bar-iron similarly treated. Examine the frac- 
tures and compare them with each other, and with 
that of good wrought-iron. Make memoranda of 
the results of all your observations. 

Next, wedge the short pieces one after the 
other in the hole of the anvil, making, if neces- 
sary, a wrought-iron wedge to hold the piece 
tightly in position, about 2" of the piece being in 
the hole. Strike the piece sideways near the upper 
end, till it is bent aside at an angle of 50° or 60°. 
Strike it on the other side and bend it back to an 
equal extent in the other direction. Try to break 
it by repeated bendings, and note how much of 
such treatment each piece will stand. Cut a si mi- 



MANUFACTURE AND PROPERTIES OF STEEL. 79 

lar inacQ of bar-iroD, and compare' this with the 
two kinds of steel. 

Next, heat one end of each piece to a cherry-red, 
plunge it quickly into water, and hold it there till 
cold. With an old file try the hard- Exercise 27. 
ness of the end thus treated, and com- Experiments 
pare with that of the opposite ends, i^ i^^^^ening. 
You find that sudden cooling from a red heat 
hardens tool-steel. You have long ago found that 
no such effect is produced on wrought-iron ; and 
you find that mild steel is in this respect much 
like wrouo!:ht-irou. 

Again, test the piece thus hai'dened for tough- 
ness, as you did before hardening it: you find it 
has become not only hard, but brittle. 

Lastly, heat about 2'^ of one end of the tool- 
steel to whiteness, and treat it as you did 
wrought-iron, in previous exercises for drawing 
and pointing. You find it brittle, like hot-short 
iron, and it is evident that it cannot be worked 
at such a heat. Try successively low^r tempera- 
tures, till you find one at which it can be forged. 
Do the same with the low steel. You will find 
hereafter that though the steel is not made brittle 
at this temperature, it has probably suffered an- 
other injury, which you will understand when you 
come to consider the subject of "hardening" and 
" tempering " steel, that it is necessary to work it 
at a still lower temperature, and that each kind 
of steel has a temperature of its own at which it 



80 FIRST LE880N8 IN METAL-WORKING. 

can be worked, and which, generally, can be as- 
certained only by trial. 

Collect, now, all the points of resemblance and 
of diiferetice that you have discovered between 
wrought-iron, cast-iron, mild steel, and high-grade 
steel, and write them out in a clear and orderly 
manner in your memorandum-book. 



WELDING STEEL: LOW GRADE. 81 



LESSON XIV. 

WELDIIS^G STEEL : LOW GRADE. 

We will make our iirst attempt at a steel weld 
witli a low-grade steel containing about ^ of 1 per 
cent of carbon. This may be eitlier a mild shear- 
steel, or a Bessemer steel of about the quality now 
used for carriao:e-tires. It will differ but little 
from wrought-iron, except that it will be tougher. 
It will be easier to Aveld than tool-steel, but will 
require more care than wrought-iron. We will 
take the tough ^" piece of the last exercise, and 
join it again to the piece from which it was cut. 

First, straighten the pieces at a dull-red heat. 
Upset and scarf one end of each piece, with the 
aid of a helper, using a fuller, and proceeding as 
in Exercise 19. Be careful to use a coke fire in- 
stead of one of green coal, and to work at a low 
heat, never exceeding a cherry-red. Unless you 
work very expeditiously, therefore, sticking always 
at exactly the right place, and without loss of 
time, you will not be able to prepare the scarf - 
piece in one heat. Beheat cautiously, 
moving and turning the piece occasion- weiding steel 
ally in the hre, and watching the color on steel: low 
closely. Keep the other piece in the 
e.dge of the lire, so that it sliall be nearly ready 



82 FIRST LESSON'S IN METAL- WORKING. 

for use when wanted, but in no danger of burning. 
Make the scarf in as few heats as possible. When 
the two surfaces are prepared, put the pieces in the 
fire side by side, as in Exercise 19, and raise them 
slowly to a cherry-red. Sprinkle the scarf -surf aces 
with powdered borax and allow it to melt, and 
spread over the surface before you put the pieces 
into the fire again. Heat them slowly, and as 
soon as the borax smokes, which will be an indi- 
cation that they have reached a cherry-red, with- 
draw them from the fire, and finish the weld as in 
Exercise 19, observing all the precautions there 
described, but remembering that, after the first 
adhesion of the two surfaces, there is not the same 
necessity for rapid work in this case as in the 
iron weld, because the steel, being worked at a 
lower temperature, does not quite so quickly fall 
below the required heat. Remember that, in this 
case as in the previous ones, it is essential to a 
good weld that you should have a bright, clean, 
and deep fire; but you should not have a broad 
one, as that will heat too much of the length of 
the pieces. Finish square, straight, and smooth, 
as in similar work with wrought-iron, and test in 
the same way. If the result is not satisfactory, 
cut out the weld on the hardee at a red heat, and 
repeat. 

Try next a split weld, of steel on iron, taking 
one end of the piece just finished, and an 8^' piece 



WELDING STEEL: LOW -OR AD E. 83 

of V square bar-iron. Make this weld without a 
helper. Upset and split the iron, and Exercise 29 
lay it in the edge of the fire to keep it Welding mild 
at a red heat while you are preparing ^*®®^ °" *^°"" 
the steel wedge-piece. This is because the steel 
must be worked at a lower temperature than the 
iron, and therefore, when they are presently put 
into the fire together, the iron should be hot and 
the steel cold, so that they may reach their proper 
heats at the same time. Hammer the steel to the 
wedge-shape, and fit the hot V-piece to it as in 
Exercise 19. Then, without letting the V-piece 
cool, place both together in a good welding fire 
and raise the steel to a bright cherry-heat, when 
the iron will probably be at a welding heat. 
During this operation keep them on the top of 
the fire, so that they can be easily watched, and 
move them about so that they shall not get too 
hot beyond the joint. In doing this, take hold of 
both pieces, and keep the wedge pressed well up 
into the split. When the joint is at the proper 
heat, take up some poAvdered borax on a bit of 
hoop-iron or small flattened bar-iron as a sort of 
spoon, and sprinkle it abundantly on the joint. 
Watch the melting of this, while you keep up the 
heat by means of the blast. When it has thor- 
oughly run into and around the joint, and the 
steel is at a bright cherry-red, take hold of the 
joint with a pair of tongs while it lies in the ^re^ 



84 FIRST LESSONS IN METAL- WORKING. 

and without removing it, squeeze it vigorously. 
This will partially weld the Joint, and enable you 
to handle the pieces with less risk of separating 
them. Remove them to the anvil, strike a few 
quick blows to make good the weld, and you can 
then finish more at your leisure, reheating the 
pieces as often as may be necessary. The finish- 
ing and testing should be exactly as in Ex. 19. 



WELDING STEEL: HIOH-QRADE. 85 



LESSON XV. 

WELDIIS^G STEEL : HIGH-GEADE. 

We will now try a weld of liigh-grade or tool 
steel, which will be somewhat more difficult to 
manae'e. Take the piece of A^' tool 

^ ^ ^ Exercise 30. 

steel of Ex. 26. Be careful to per- weiding high- 
form all operations on it at a tempera- s^^^de steel on 
ture lower than that at which you have 
found that it becomes brittle. Upset it as in the last 
exercise, holding the piece this time in the vise for 
the purpose,. In upsetting in the vise it is easier 
to prevent bending, if you are careful not to strike 
too hard. On the other hand, if you set the 
piece too low in the vise you will limit the upset- 
ting to the extreme end, and the work will turn 
out too thin when the weld is finished. While 
upsetting, keep the piece square and straight by 
occasional hammering on the anvil. With this 
kind of steel you will probably have to reheat 
each piece several times for each operation, which 
will do no harm unless you make it too hot. 
When it is properly upset, split it, again at a red 



86 FIRST LE8S0JVS IN METAL- WORKING. 

heat, holding it upright in the vise and using a 
thin hot-chisel. When the cut has been made to 
the proper depth, widen it a little with a duller 
chisel, spread the lips, form the wedge-piece, and 
drive it in till it reaches quite to the bottom of 
the cut, all as in previous exercises of the same 
kind. Put the pieces together and fit them as 
closely as you can, at a red heat. They are now 
to be heated together in the fire, with even more 
caution than in the last exercise as to the charac- 
ter of the fire, the mo vino;; about in the fire to heat 
all parts of the Joint but without parting the 
pieces, and the keeping within proper limits of 
temperature. Sprinkle abundantly with borax 
without removing from the fire, pinch together in 
the fire, and weld and finish, all as in the last ex- 
ercise. 

This will probably be found to be a rather dif- 
ficult task, and you may have to try several times 
before succeeding. Some of the causes of failure 
are the following : 

1°. Overheating at any stage of the operation, 
which will cause the steel to break or crumble 
under the hammer. 

2°. Underheating at the time of welding, 
which will prevent the pieces from uniting. 

3°. Dirty fire, letting cinders get into the Joint. 

4°. Too much thinning of the lips of the V- 
piece, which will make the Joint so weak that it 



WELDING STEEL: HIGH-GRADE. 87 

may be impossible to keep the two pieces together 
iu the fire, or while removing them to the anvil. 

5°. Too short a notch, leaving part of the 
thinned wedge exposed. 

6°. Loss of time in striking, after removing the 
work from the fire. 

7°. Imperfect contact of the edge of the wedge 
v^dth the bottom of the notch, leaving a hole, or, 
if this is closed by hammering, leaving the piece 
too thin. 

8°. Imperfect union of the edges of the lips of 
the V-piece with the sides of the wedge, owing 
to burning of the edges, which often happens if 
they are too thin. 



88 FIBST LESS0N8 IN METAL- WORKING. 



LESSON XVI. 

HARDENING AND TEMPERING STEEL. 

You have learned (Lesson XIII., p. 79) that 
high-grade steel, when cooled from a red heat by 
plunging into water, becomes very hard. The 
same effect, with some differences in degree which 
need not be considered yet, results when the steel 
is cooled suddenly from the same temperature in 
any other way, as by plunging into oil or tallow, 
or even, if it is a thin piece, by contact with a 
large mass of cold metal, such as the anvil. Again, 
you have found that the piece which has been 
thus hardened has also been made brittle. In 
some tools, as in those intended for cutting metals 
and stone, this property of hardness is of great 
value ; but on the other hand, the brittleness which 
accompanies it may very much lessen this value. 
The sharp corner of a scrap of glass, for instance, 
is hard enough to scratch iron or steel; but the 
brittleness of glass makes it worthless as a mate- 
rial for cutting-tools, as its sharp edge is quickly 
broken off*. The same is true of very hard steel. 
It is important, therefore, to understand exactly 



HARDENINO AND TEMPERING STEEL. 89 

the means by which this hardness is produced, and 
the means by which the brittleness can be dimin- 
ished without sacrificing too much of the hardness. 
In the first place, the amount of hardness pro- 
(1 need by sudden cooling depends on the tempera- 
ture from which the cooling takes place. Perform 
the following experiment to satisfy yourself of 
this. Take four pieces of high-grade octagon or 
round tool-steel, \" or f^'in diameter and 2" long. 
Mark them, near one end, with file-scratches, so 
that you can identify them. Let them lie for fiYO; 
minutes, one in boilinc^ water, one in boilinof lin- 
seed-oil, one in red-hot melted lead, and one in the 
fire till it is as hot as it can be made without burn- 
ing. (The oil may be boiled in a small iron ladle 
on a dull forge-fire with a very gentle blast, takiug 
care not to let it boil over, and, if it takes fire, 
raising it from the fire and letting it cool a little, 
so that you can blow it out, but without removing 
it from the forge, for fear of accident. The lead 
may be melted in a similar ladle, or in the same 
one after the oil has been poured off and the rem- 
nant of it burned out. The lead must be red- 
hot.) The first of the four pieces will then be at 
a temperature of 212° F., the second at about 580°, 
the third at about 1500°, and the fourth at about 
2500°. Picking up each piece with a small pair 
of tongs which have been standing in the fiuid or 
the fire so that their jaws are at the same temper- 



90 



FIBST LESSONS IN METAL- WORKING. 



ature as tlie j)iece of steel and will not cliill it, 
drop each into cold water. 

Test them, as to hardness, in the following way: 
Clamp the piece in a hand-vise, as in Fig. 54, let- 
Exercise 31. ^ng it project about \" at the side of 
Experiment the vise. Fasten the hand-vise to a 
T 1^ ^"^"^ piece of wood four or five feet long 

and 3^' wide, with a 
screw and washer, as in 
the same figure. Sup- 
porting one end of the 
Fig. 54. strip on a bench or 

table, and preventing it from shifting by means 
of a nail passing through an auger-hole, let the 





Fig. 55. 



end of the piece of steel rest on the grindstone 
Hang a weight of 8 or 10 lbs. on the strip, to pro- 
duce a suitable pressure on the stone, making a 
notch for the cord so that it shall be attached at 
the same place in all the experiments. Let the 



HARDENING AND TEMPERING STEEL. 91 

piece bear on the stone, keeping it well watered, 
and grind the end square, moving it to and fro 
sideways, so as not to wear the stone in one place. 
When all the ends ai'e square, weigh the pieces, 
and record the weight of each. Then grind off 
from each as much as the stone will remove in 
1000 or 1500 revolutions, and weigh the pieces 
again. The percentage of loss of weight w^ill in- 
dicate the softness of the pieces, since all have 
been treated alike. You can therefore arrange 
the pieces in the order of hardness, and can learn 
the effect of sudden cooling from these tempera- 
tures. 

Next, holding the pieces in succession on the 
anvil, and striking them at the end with the ham- 
mer, first gently, and then more forcibly, you can 
learn, in a general way, which are the most brit- 
tle, though this experiment is only a rough one, 
and its results cannot be expressed in figures. 
Make a record of these results, and remember 
them. 

The hardness produced by sudden cooling from 
a red heat can be entirely removed by cooling the 
metal slowly from a red heat ; and the more 
slowlv it is cooled, the softer and touo^her will the 
steel be. The brittleness and the hardness are 
reduced together„ Experiment on this in the 
following way: Heat three pieces of steel, such as 
you used in the last experiment, to a bi'ight red 



92 FIRST LESSONS IN MB TAL- WORKING. 

heat in melted lead, having, as before, marked 
them for identification. Harden them 
Experiment" all alike, by plunging them suddenly 
on annealing ^j^to cold Water. Then, heating them 
to a bright red again, cool them in the 
following ways : 

No. 1, by holding it in the tongs (previously 
heated to a ^' black red") and letting it cool in 
the air till the redness is invisible in the light, 
but just visible in a dark corner, and then plung- 
ing it into water. 

No. 2, by laying it on the loose cinders in the 
forge, and letting it cool slowly in the air ; and, 

No. 3, by leaving it, red-hot (but not white-hot), 
in the fire, well covered with the coals and cin- 
ders, letting the fire go out, and leaving it there 
till quite cold. 

Test these pieces for hardness and brittleness, 
as in the last experiment. You will find that the 
steel has recovered more or less of its toughness, 
and also of its softness, by this gradual cooling. 
This process is called annealing; and the three 
methods you have just tried are called water, air, 
and fire annealing. Make a record of the effects 
of each, and remember them. 

It is usually said that while cooling suddenly 
from a red-heat hardens steel, cooling from a 
lower heat, whether slowly (as in the air) or 
quickly (as in No. 1 of your last experiments), 



HARDENINO AND TEMPERING STEEL. 93 

softens it. Try to ascertain from your experi- 
ments whether these statements are correct. 

Glass is very much like steel in the effects of 
heat on it, while some metals and alloys, as cop- 
per and brass, behave, as you can now easily 
prove by experiment, in exactly the opposite way, 
being hardened by slow cooling and softened by 
rapid cooling. 

You have found now that, in general, the harder 
steel is, the more brittle it is, and the tougher the 
softer. It is therefore impossible to retain the 
highest degree of hardness with great tough- 
ness; and for each particular use to which steel 
is to be put we have to try to secure the particu- 
lar degree of hardness and toughness most nearly 
suited to that use. 

As your experiments show that the hardness 
and toughness of steel depend on the temperature 
from which the metal is cooled, and as small dif- 
ferences in toughness may suffice to make a tool 
very valuable or altogether useless for a given pur- 
pose, it is important to know how to select the 
right temperature for each case. The red which 
is Just visible in the dark (or black-red, as it is 
called) is a very good indication of one tempera- 
ture—about 500° to 525° C, or 932° to 977° F. ; 
but sudden cooling from this point gives a hard- 
ness which, though it serves very well for files, is 
too great for most other tools. If a tool which 



94 FIRST LESSONS IN METAL- WORKING. 

has been thus hardened too much be raised again 
to some lower temperature, and then cooled from 
that temperature, it will be softer than before ; 
and by selecting the proper temperature it will be 
possible to give it any lower degree of hardness 
that may be required. This process is called 
'' letting down" or "tempering." Success in tem- 
pering depends — 

First, on the selection of the proper tempera- 
ture; 

Second, on the method of applying the heat; 
and. 

Third, on the method of cooling. 

We will consider these three subjects sepa- 
rately : 

1. The temperature used, when it is lower than 
the black-red heat, is indicated by the color which 
is assumed by a brightened portion of the surface 
of the steel. Ii'on or steel when heated in the 
air oxidizes on the surface. Grind two or three 
inches of the surface of an old flat file, making it 
bright on one side. Heat a piece of 1" bar-iron, 
« . «^ 15'' or 20'^ long:, to a bris^ht red at one 

Exercise 33. ^/ . (, . . . 

Experiment end, and lay the piece of brightened 
on colors of gtccl ou it, in a good light, with the 
bright part projecting about an inch or 
two beyond the end of the hot bar. The project- 
ing part will be cooler than the rest, and the heat 
will travel along to it gradually. Fix your atten- 



HAUDENINO AND TEMPERING STEEL. 95 

tioii on the end, and watch and record the several 
colors as they appear there, one after the other. 
These colors are produced in the same way as the 
colors of the soap-bubble, and, like them, they 
change with the thickness of the very thin film 
which causes them. As the temperature of the 
steel rises the thickness of the film of oxide of iron 
increases, and the color changes. The color is 
therefore an indication of the thickness of the 
film, and that in its turn shows the temperature 
of the metal. It has been found that the tem- 
peratures corresponding to the several colors are 
as follows : ^ 

1. Very pale yellow, . . . 221° C. or 430° F. 

2. Pale straw, 232 " 450 

3. Full yellow, 243 " 470 

4. Brown, 254 " 490 

5. Brown, with pur23le spots, 265 " 510 

6. Purple, 277 " 530 

7. Bright blue, 288 " 550 

8. Full blue, 293 " 560 

9. Dark blue, 316 " 600 

If a piece of steel whicli has been hardened be 
heated to one of these colors and then cooled, it 
will be softened, and the higher the temperature 
to which it has been raised the softer it will be. 
Try this in the following way : Take three pieces 

* Percy's Metallurgy. 



96 FIB8T LESSONS IN METAL- WORKING. 

of octagon steel, as in your last experiments, and 

harden them by plunging them in water at a red 

heat. Rub them on a piece of srrind- 

Exercise 34. i i • i x 

Experiment stouc or othcr saudstoue to brighten 
on tempering them. Lay them on a red-hot bar of 

steel. . , -\ ^ £. J. 

iron supported over a vessel oi water. 
When any one of the pieces shows a pale-straw 
color, push it off into the water. Do the same 
with the others when they reach a light purple 
and a dark blue respectively. Now, using an old 
file, try how much of each piece you can remove 
by a given number, say fifty, of similar strokes of 
the file, and thus compare the results obtained by 
tempering from these various temperatures. You 
might measure the hardness on the grindstone, 
but it is well also to get accustomed to judging 
the hardness approximately by the way the metal 
feels under the file. 

It is generally stated that the colors in the pre- 
ceding table indicate the proper temperatures for 
the following objects, respectively :^ 

No. 1. Lancets. 

2. Razors and surgical instruments. 

3. Penknives. 

4. Small shears, chisels for cold iron. 

5. Axes, planes, pocket-knives. 

6. Table-knives, large shears. 



* Percy's Metallurgy. 



HARDENING AND TEMPERINO STEEL. 97 

7. Swords, springs. 

8. Fine saws, daggers, augers. 

9. Saws. 

As your future exercises give you opportunity, 
you ought to compare tliese results with those of 
your own experience, remembering the agree- 
ments, and the differences if you iind any, and 
noticing any peculiarities in the behavior of differ- 
ent kinds of steel, so as to know how to treat dif- 
ferent kinds when particular results are sought. 

The three pieces tempered in the last experi- 
ment may be tested also as to toughness, by hold- 
ing them one after the other in exactly the same 
way in a vise, and striking them on one side in- 
creasingly heavy blows with the hammer till you 
break them. No very exact result will be reached 
in this way, because you cannot measure the 
energy of your blows ; but you can form an ap. 
proximate estimate of the toughness of the pieces. 



98 FIRST LESSONS IN METAL- WORKING. 



LESSON XVII. 

HAEDEIS^ING AND TEMPERINa ^TYIEL.— Continued. 

We come now to consider — 

2. The metliod of apply log heat. 

When a piece is to be hardened all over alike, 
it is important that it should have the same tem- 
perature throughout. It may, if not too small, 
be heated in the forge-fire ; but it must be moved 
about, so that all parts may be exposed to the 
heat, and must be heated slowly, so that all may 
have time to arrive at the same temperature. 

The hollow fire is useful for this purpose, as it 
allows the piece to be watched closely, and in- 
sures the heating of the top as well as the bottom. 
If the piece is small, an excellent plan is to im- 
merse it for some minutes in red-hot melted lead. 
The piece quickly takes the temperature of the 
lead, and care must therefore be taken not to 
allow the latter to rise to the point at which 
it would injure the steel. The lead must be 
watched, and if it is found to be getting too hot, 
it must be cooled by putting the end of a bar of 



HARDENTNO AND TEMPERING STEEL. 99 

cold iron into it. The pieces slionld be rubbed 
with soft soap before immersiDg them, to prevent 
the lead from sticking; or a paste made of black- 
lead and water may be used ; but in this case 
care must be taken to let the paste dry before im- 
mersing the piece, as otherwise the steam produced 
may scatter the lead in a dangerous way. 

If small objects be removed from the lead with 
cold tongs, they ^vill be irregulai'ly cooled. It 
will be well therefore to let the ends of the tougs 
lie iu the lead for some time ; or they may be 
first heated iu the fire, and then stood in the 
lead till wanted; or the piece may be held by 
means of a piece of soft wire twisted rouud it as a 
handle. 

The heat for auuealing may be applied iu the 
same way as that for hardeniug. The heat for 
tempering would be more difiicult to manage if it 
were always necessary that all 23arts of the piece 
should have the same tem23erature, because all 
will not reach this temperature, or show the cor- 
responding color at the same time. Fortunately, 
however, this is seldom required. It is always, 
for instance, the edge of a cutting-tool that is to be 
tempered ; the exact condition of the rest of the 
tool is not so important. It is the face of a ham- 
mer, the 2^oint of a drill, the iipper surface of an 
anvil, that is to be tempered, and it is on these 
that the attention is to be fixed while the piece is 



100 



FIRST LES80NS IN MBTAL-WORKINO. 



being heated. Small objects, therefore, such as 
drills and knife-blades, may be heated on a hot 
bar and pushed off at the right time; or small 
drills may be heated in the blue part of the flame 
of a candle, applied just behind the point, so that 
the color of the point may be watched. Larger 
objects, such as chisels, cold-chisels, hatchets, and 
rock-drills, may be still more conveniently tem- 
pered at the edge by means of the heat left in the 
rest of the tool after the edge is cooled. The 
making and tempering of a cold-chisel will afford 
a good illustration of this very useful method. 

Take a bar of f ^' octagon tool steel. Cut off a 
piece ^" long by nicking it all round on the 
Exercise 35. l^^rdee at a red heat, cooling it quickly 
Making a in watcr, and then breaking it off as 
cold-chisel. .^ Exercise 26. Be careful not to hit 
so hard as to make the piece fly, and not to place 
it in such a position that, if it does fly, it can hurt 

anybody. Working at a red 
heat and avoiding overheat- 
ins:, draw one end down to a 
bevel extending back about 
To do this, hold the 



piece on the anvil, resting 
obliquely on it at the farther 
edge, as in Fig. 5 6, and strike 
Fig. 56. it with the hammer inclined 

at a little larger angle. Both the opposite faces 




Ql^^ 



HAKDENING AND TEMPERINO STEEL. 



101 



will thus be flattened at once. The angle of the 
faces should be about 16°, which it will be if 
the thickness of the steel is ^" and the length 
of the bevel ^\". If the angle is much larger 
than this it will not allow the workman to have 
a good view of the edge of the tool in using it ; if 
much smaller, the tool will be too thin and will 
spring too much. In flattening the bar you will, 
of course, spread it sideways also, as in previous 




Fig. 57. 

scarfing exercises. Reduce the bar again nearly to 
its former width at the edge, by hammering on 
the sides. Cut off the ragged edge at a red heat, 
on the hardee, being very careful not to strike the 
edge of the hardee with the hard face of the ham- 
mer. It Avill be safer to do this with a hot-chisel 
and the assistance of a helper. Hold the bar on 
the anvil with the left hand, the edge projecting 



102 FIRST LESSONS IN METAL-WORKING. 

about \" over tlie edge of the anvil. Set tlie hot- 
chisel over it, as in Fig. 57, and hold it with the 
right hand while the helper strikes it with the 
sledge. Take care that the chisel as it cuts 
through shall pass just clear of the edge of the 
anvil, shearing the piece off without injury to the 
chisel. 

You need not be afraid of injuring the steel by 
too much hammering, or by hammering after it 
has fallen below the red heat. Unlike iron, it is 
improved by hard work on the anvil, having no 
fibres which can be separated by hammering. 
Finish the faces with the flatter, as in Exercise 18. 

You are now ready for the annealing, harden- 
ing, and teniperiug. Heat the whole chisel to a 
cherry-red, slowly and uniformly, as explained in 
Exercises 28-30. Hold it in the tongs by the 
upper end till it has reached a black-red heat, and 
then plunge it endways, edge first, into cold 
water, immersing it completely, and leaving it 
there till cold. The tool is now annealed. All 
the inequalities of hardness which may have re- 
sulted from the diffei'ent treatment that different 
parts of the tool have received during the forging 
are removed, and the whole tool is soft enough to 
be sharpened with a file. 

To harden and temper the edge, raise about 2" 
at the cutting edge to a red heat. Holding it in 
the tongs with the edge downward, lower it into 



HARDENING AND TEMPERING STEEL. 103 

the water to the depth of about 1". Then grad- 
ually raise it till about half an inch is immersed, 
and hold it there, either still or moving gently to 
and fro sideways, till the edge is cold. The object 
of this movement upward is to prevent a too ab- 
rupt change from the cold to the warm part. If 
the chisel is immersed to a given depth and held 
steadily there, the boundary between the hard and 
the soft part is too distinct, and the chisel is al- 
most sure to break at that place. 

The edge is now hai*d — too hard for use, and 
is to be tempered. Rub one of the surfaces for 
about \" back fi'om the edge ^vith a piece of sand- 
stone to brighten it, and then watch carefully for 
the appearance of the proper color at the edge, as 
the heat comes along from the other part of the 
chisel. What the proper color is, depends on the 
use to which the tool is to be put. We will 
suppose this one to be intended for cutting cast- 
iron, in which case the proper color is a light pur- 
ple. As the colors move along toward the edge, 
the purple an ill be followed by the dark blue, and 
when the latter has almost reached the edsre the 
former will have reached it, and it is then time to 
plunge the whole chisel into water, and move- it 
about till it is cold. The experiments you have 
already inade have taught you Avhat to do if you 
require a harder or a softer temper than this. 

The cutting-angle of the chisel is formed on the 



104 FIRST LESSONS IN METAL-WORKING. 

grindstone, and extends back only about \" from 
the edge. The size of this angle, as well as of 
that between the two forged faces, depends on the 
use to be made of the tool. The latter angle may 
be 12° to 15° for brass or copper, and 16°, as in the 
one just made, for iron. The cutting-angle should 
be about 30° to 35° for copper, 50° for brass, 65° 
for cast-steel, and 80° for cast-iron. 



HAUDENING AND TEMPERING STEEL. 105 



LESSON XVIII. 

HAKDElsriNa AND TEMPEEING ^T^^Jj.— Continued. 

We liave next to consider — 

3. The method of cooling. The piece of steel, 
when heated, may be cooled, either for the pur- 
pose of hai'dening or of tempering it, by plunging 
it into any fluid which is a good conductor. The 
better the conductor is, the more quickly will the 
piece be cooled, and therefore the harder will it 
be. Hence, when the highest degree of hardness 
is required, mercury is sometimes used. Water, 
oil, and tallo^v, which are inferior conductors, give 
successively lower degrees of hardness. Water 
is the material most commonly used, and, for 
pieces which require more toughness and elas- 
ticity, as s^D rings and small drills, oil. In temper- 
ing also, as well as in hardening, the fluid is varied 
according to the J'esults sought, water and oil, 
however, being generally used, and even air when 
the piece is very small. 

To illustrate these points we will make, first, a 
flat spring, and secondly, a small drill. 



106 



FIRST LE880NS IN METAL WORKINO. 



For the first, take a piece of |'^ round tool-steel 
about 10'' long. Heat ?>" of the end, with proper 
precautions against burning, and flatten it till it is 
\" wide. Make it quite straight, and of exactly 

Exercise 36. i^iiif^^i'^^ width and thickness, using 
Making a a flatter if necessary. Finish it as 
spring. smooth and free from scale as pos- 

sible, as scales will prevent it from heating uni- 
formly all over. With a small punch make two 
holes \" in diameter in one end, being careful not 
to split the piece in finishing. Bend it as in Fig. 
58, by heating the end to a dull red, laying it 




Fig. 58. 



over the edge of the anvil, and hammering as in 
Exercise 5. Be careful not to make the bend too 
sharp, but rather curved, or you will weaken the 
steel at that point. Bend the other end in the 
same way. When the spring is finished, nick the 
piece with a file at the base of the spring, and. 



HARDENING AND TEMPERING 81 EEL. 107 

holding it in the vise, with the nick just visible 
above the jaws, break it off by bending. 

To anneal and harden the spring, provide a jar 
of linseed-oil four or live inches deep. Tie a piece 
of light wire 8'' or 10'' long to one end of the 
spring as a handle. Heat the spring to redness, in 
melted lead, and let it cool slowly on the ashes 
beside the lire. Heat it again to redness, and 
plunge it endways into the oil. If several students 
are w^orking together, some may try the effect of 
immersing it sideways. You will pi'obably find 
that in this case the spring is bent by the unequal 
cooling of the opposite edges, and will thus learn 
the advantage of immersing such pieces end- 
ways. 

The spring being hardened, is now to be tem- 
pered. This requires that it be raised to the 
temperature indicated by a deep-blue color, or 
about 560° F. The thinness and crookedness of 
the piece will make it nearly impossible to do this 
properly, either in the fire or on a I'ed-hot bar. 
Put it into a ladel of cold oil, and heat it gradually 
to boiling, with the precautions against accident 
indicated on p. 89. At various stages in the 
boiling the oil will have different temperatures, 
which are easily recognized. When a light white 
smoke begins to come off, the temperature is about 
the same as that indicated by a straw-color, or 
about 450° F. A copious dark smoke is equiva- 



108 FIRST LESSONS IN METAL- WORKING. 

lent to a brown color, and a still more abundant 
black smoke to a purple. At a little liiglier 
temperature tkan this, the oil will burn if ignited, 
but can be put out by blowing it. This tempera- 
ture is equivalent to a blue color, and will be 
suitable for tempering the spring, if it is made of 
a low^-grade steel. At a still higher temperature 
the oil sw^ells up and boils vigorously, takes fire 
on the surface and burns continuously, igniting 
again if blown out. This temperature is suitable 
for the spring if it is made of high-grade steel. 
At the proper temperature, remove the spring 
from the oil by the wire handle, and cool it in the 
air, in water, or in cold oil. The difference between 
these methods wall be slight in such a small piece. 
Set the oil aside in the forge till it cools off, after 
which it can be put away for future use. 

To test the spring, hold it in the vise by the 
end, straighten it, and let it go two or three times. 
It should completely regain its figure. If it 
breaks, it is too hard, and the tempering heat Avas 
not high enough. If it does not return, it is too 
soft, and the heat was too great. 

As a last exercise in forging and tempering 
steel, make a small drill (y) such as is shown. 
Exercise 37. enlarged, in Fig. 59. Take a piece of 
Making a steel wire -f-^'' thick and ^" or 8^^ long. 
^"^^" On a small bench anvil, and using a 

light hammer, draw it out, at a dull-red heat to 



HARD EN [NO AND TEMPERING STEEL. 



109 




c 





the form shown in Fig. 59. The flame of the 
Bunsen burner may be used 
for this, or the forge-fire, if 
very great care is taken. First 
draw out the narrow part, or 
shank of the drill, turning it 
constantly to preserve its 
roundness and keeping it quite 
straight. Next flatten and 
widen the end. Finish it 
smooth, cut it off, and anneal 
it at a black-red heat. Finish 
the flat faces on the grind- 
stone, and then form the two 
bevelled surfaces, by holding 
it on the grindstone or the 
emery-wheel as in Fig. 60, 
cutting it back to the dotted 
line, and then turning it over 
and cutting to the other clotted 
line. Observe that the faces 
that you are now forming are 
to be, as shown at b and o, 
not perpendicular to the flat 
faces, but inclined to them 
The inclination, which constitutes the cutting- 
angle of the tool, depends, as in all other cutting 
tools, on the hardness of the material on which it 
is to work. If, as you hold the drill between the 



Scale, % 

Fig. 



59. 



110 FIRST LE880N8 IN METAL-WORKINO. 

tlmmb and finger in grinding it, you turn tlie 
thumb a very little over toward the right, you 
will make a drill suitable for one kind of work, 
and if you turn it a little farther, one suitable for 
softer material. Your drill, when finished, will 
have, as you see on examining the figure or the 
drill itself, not a point, but a short blunt edge, 
running obliquely across the end, as shown in the 
end elevation (7. 




Fig. 60. 

The drill is now to be hardened and tempered. 
To harden it, hold the point in the flame, watch 
it till it reaches a cherry-red, and then plunge it 
into water. The butt of the drill will thus be 
left soft. Brighten the point, and hold it again 
in the flame, the point being this time just out- 
side, so that the color can be seen. The color, 
Avhich, in the case of such a small piece as this, 
Avill appear very soon, should be brow^nish yellow 
if the drill is intended for iron, and purple if it is 
for wood. The moment the color appeal's, plunge 
the drill quickly, point downwards, into cold oil. 



HARDENING AND TEMPERING STEED 111 

The fiual finishing on the grindstone is done after 
the tempering. 

A still smaller drill may be hardened by heat- 
ing the point in a candle-iiame, and cooling it in 
the tallow of the candle. It is then tempered, by 
covering the point lightly with tallow, holding 
the stem just behind the point in the ilame till it 
begins to give off a white smoke, and then cooling 
it either in the tallow or in the air. 

The exercises in hardening and tempering that 
you have now gone through will give you a suffi- 
cient comprehension of the general principles of 
the process. A great variety of modifications of 
the methods will be needed for ^vorks of different 
sizes and shapes, and intended for different uses ; 
but these will be easily nnderstood when the 
necessity for them arises. 

It might be supposed that, as cast-iron differs 
from steel in the same way that steel differs from 
w^rought-iron, namely, in having more carbon in 
its composition, it might be hardened and soft- 
ened in the same w^ay. This is to a certain extent 
true. Cast-iron can be hardened by rapid cooling ; 
but it requires a much higher temperatui'e for the 
purpose than steel does. It must be cooled, not 
merely from a red heat, but from the melting heat. 
If cast-iron, when melted is poured into nionlds 
of damp sand or of metal, it becomes very hard 
on the surface. Such metal is called "chilled 



112 FIB8T LE8S0N8 IN METAL-WOBKINO. 

iron/' and is sometimes used when great hardness 
is required at moderate expense, and without re- 
gard to toughness, as in ploughshares, ore-stamps, 
rollers for pressing or crushing, and sometimes in 
tools for turning iron and steel. Such metal, 
however, is brittle and cannot be tempered, and is 
not a fit substitute for steel in most of the uses to 
which the latter is put. 

Even when cast-iron is not intentionally chilled, 
it is unavoidably hardened on the surface by the 
chilling action of the mould, and this is one of 
the reasons why the hard " skin" is commonly re- 
moved with the chisel or planing-machine before 
applying the file. 

As cast-iron can be hardened by chilling, so 
wrought-iron can be hardened on the surface by 
baking it, at a red heat, w^hile surrounded with 
powdered carbon. The resemblance between this 
process and that of steel-making by cementation 
is seen at a glance. Indeed, it is an imperfect 
conversion of the iron into steel on the surface. 
It is called ^' case-hardening," and is used for such 
objects as the wearing parts of gun-locks, the ends 
of axles, and other objects exposed to great wear 
by rubbing. 

Finally, as wrought-iron can be hardened, so, 
by an almost exactly opposite process, cast-iron 
can be softened. As wrought-iron is hardened 
by absorbing carbon, so cast-iron is softened by 



HARDENING AND TEMPERING STEEL. 113 

being made to give up carbon. For this purpose 
it is packed in a substance containing oxygen, 
sucli as lime (calcium oxide) or the scales from 
the blacksmith's forge (iron oxide), and baked at 
a red heat. A part of the carbon combines with 
the oxygen, and escapes as carbonic oxide, leaving 
an iron with a lower percentage of carbon, and 
therefore I'esembling wrought-iron or mild steel. 
Such iron is called " malleable" iron, and is much 
used for small articles which require more tough- 
ness than cast-iron possesses, but which are to be 
made in large numbers, and with a cheapness ap- 
proaching that of cast-iron. Hinges, gate-fixtures, 
parts of harness, and a great number of small 
household articles are made in this way. 

It must be understood, however, that not every 
kind of pig-iron can be used for the several kinds 
of iron that have been described, but that one pig 
or another, or a mixture of several, must be used, 
according as high or low steel, foundry iron, 
chilled iron, good forge iron or malleable iron is 
required; and great skill and experience are 
necessary to enable the iron-manufacturer to make 
the proper selection in each case. 



114 FIBSl LES80NS IN METAL- WORKING. 



LESSON XIX. 



CHIPPING. 



Objects made of iron, steel, or brass by casting 
are frequently too rough to be used in the form 
in which they come from the mould, and have to 
be finished up by filing, grinding, scraping, and 
polishing. Sometimes, also, it is necessary to take 
off more metal than can be conveniently removed 
by the file. On large and flat surfaces this may 
be accomplished by means of a planing-machine ; 
but on surfaces that are small, or of such a shape 
that the planer cannot reach them, the part to be 
removed is taken off by " chipping " with a cold- 
chisel, that is, a chisel which can be used without 
first softening by heat the substance which is to 
be cut. 

Two kinds of chisel, shown in Fig. 61, are used. 
Tlie first. A, called a '■' cape" or cross-cut " chisel, is 
made thin at c, but is widened, as shown at a^ 
to f^ive it the needed sti'eiisrth. It is used in cut- 
ting grooves. Being thinned at a little distance 
back from its edge, it can be driven along the 



CHIPPING. 



115 



groove without catching at the sides, while the ex- 
tra width at a prevents its ^'spiinging" under the 
blow. The other, B^ is the " finishing " or " plan- 
ing " chisel, and is used for cutting broader plane 
surfaces. It is sometimes ground with a slightly 



z::^ 



p^^ 



L^^ 



rr 





_.i 



Fig. 61. 



curved edge, in which case a very thin cut can be 
made at the middle while the corners are not 
cutting at all. Its action in this case is much like 
that of the jack-plane, and leaves a series of shal- 
low valleys on the surface that is finished with it. 



116 FIRST LESSONS IN METAL-WOBKING. 

Tlie cMsel is tempered, as in Lesson XVI, to a 
color which may range from yellow to purple, ac- 
cording to the work it is to do. It will splinter 
if it is too hard, and will turn up or become 
rounded on the edge if too soft, and must then be 
re-tempered. In any case, its edge must be kept 
sharp by frequent use of the grindstone. The 
angle also depends on the kind of work, as has 
been explained in Lesson XVII. 

As an exercise in the use of the chipping-chisel, 
we will remove \'' from the surface of a cast-iron 
block ^" square. We will first cut three grooves 

Exercise 38. ^" ^^'^^^ ^^ ^^^ required depth, leaving 
Chipping four surfaccs ■^-^" wide to be after- 
cast-iron, wards cut down with the finishing- 
chisel. It will be found that the work can be 
done more easily in this way than by cutting the 
whole surface at once with the finishing-chisel. 
Lay out the face of the block for this work by 
first rubbino; it all over with chalk, and then 
drawing the necessary lines with a sharp-pointed 
steel '^scriber" or marking-tool. Mark also, on 
the edge, a line showing the depth to which the 
work is to be cut. Put the block in one of the 
heaviest vises on your bench. If there is a " leg- 
vise," Fig. 62, use this, as being firmer than any 
other. Place the block in the vise, with the lines 
indicating the grooves perpendicular to the jaws, 
and with the upper surface of the block only just 



CBIPPING. 



117 



above the edge of the jaws, and fasten it very 
iirmly. Make sure that the liead of the chisel 
and tlie face of the hammer are c[iiite free from 
any trace of grease; by rubbing tliem on the dusty 




Fig. 63. 

floor. You will thus lessen the chance of the 
hammer's glancing off and striking your hand. 

In vise-w^ork hold the hammer less tightly than 
in forge-work. Let it turn somewhat loosely be- 
tween the forefinger and the thumb. 

To begin the chipping, set the edge of the 



118 FIRST LESSON'S IN METAL-WORKING. 

chisel at one end of the line drawn on the face, 
and, holding it horizontally, strike it a vigorous 
blow, cutting off a triangular chip, and making a 
chamfer or bevel, as shown by the dotted line in 
Fig. 63. Extend this along the whole length of 
the end of the block, thus marking conspicuously 
the depth to which the metal is to be removed. 
Turn the piece in the vise, and cut a similar cham- 
fer round each of the other pieces in succession. 



^rni 




Fig. 63. 



Now, using the cape-chisel, set it on the bev- 
elled surface, at the end of one of the proposed 
grooves, and with the edge about \" below the 
upper surface, as in Fig. 64. Incline the handle 
upwards, so that the lower cutting-face shall make 
a very small angle, abd, with the intended direc- 
tion of the cut, ahc. Hold the chisel firmly, near 
the upper end, and keep your eye on the cutting- 
edge, not on the handle. Using a hammer of 
about If to 2^ lbs. weight, with a handle 13'' to 
lA:" long, which you hold near the end, strike 
the chisel with a vigorous swing of the hammer 
from the elbow. Be careful to strike exactly in 



CHIPPING. 



119 



tLe direction of the leiigtli of the chisel, so that 
it shall not receive any twist from the blow, but 
move directly forward. It will cut off and curl 
up a stout chip, exactly as the iron of the jack- 
plane does, and being continually driven forward, 
will Avork a shallow groove across the block. It 
is important that you should hold the chisel at 
the proper inclination. If the handle is held too 




Fig. 64. 

low, as in Fig. 65, the edge w411 be inclined up- 
ward at Z*, and the tool will run up and leave the 
cut. If it is held too high, as in Fig. ^'o, the 
point will be driven too far into the metal, and 
the cut will become so deep that the chip will 
not curl up and break off, but the tool will be 
brought to a standstill. 

After the cut is started, you WiWfeel the proper 



120 



FIRST LE880N8 IN METAL-WOHKING. 



position of the chisel, by rocking it up and down 
slightly, as you would rock a wood-chisel on the 
oil-stone, to ascertain when the bevel - surf ace 
touches the stone properly. 




Fig. 66. 



It is important, also, to strike powerful blows 
with a free swing of the hammer from the elbow. 
Light blows often repeated will not serve the 
same purpose : they will not cut and shatter the 



CHIPPING. 121 

metal. You may strike light blows at first, to 
get your aim sure and your hand steady, but they 
will not have much effect on the metal. Even at 
the risk of striking your left hand occasionally, 
you must hit hard. 

In cutting the grooves, stop at about \" from 
the end, and cut the opposite way, to avoid splin- 
tering the metal. 

In cutting wrought-iron, steel, or brass, wet the 
edge of the chisel occasionally, by pressing it on 
a bit of wet rag or cotton-waste kept for the pur- 
pose. 

A second and a third cut being made in the 
same way as the first, you ^vill cut one of the 
grooves, and afterwards all the others, down to 
the required depth. Be careful not to go below 
this depth at any point ; to fall short of it will 
do less harm. 

Having cut all the grooves with the cape- 
chisel, cut down the bands between them with 
the planing-chisel. If you have cut the grooves 
to just the right depth, they will afford such per- 
fect guidance to your chisel that you will cut the 
rest of the surface with comparative ease. 

If the work has been well done, the surface 
will be uniformly marked all over with parallel 
shallow notches, about equidistant and of equal 
depth, indicating the successive forward steps of 
the chisel. In perfect work, indeed, no such 



122 



FIRST LESSON'S IN METAL-WORKING. 



notches would be seen, because each forward 
movement would be in the continuation of the 
preceding cut. In practice such a result is not 
to be expected ; but you should aim to come as 
near it as possible. 

The chipping of brass is similar to that of cast- 
iron. The tool, however, may be thinner, and 
have a smaller angle, as already explained. It 
may also be wider (say 1''), as the same blow that 
will drive a narrow chisel through cast-iron wdll 
drive a wider one in brass. For an exercise in 
brass-chipping, take the block prepared as a foun- 
dry exercise, page 64, Fig. 50, and chip it to the 
form of a hexagonal prism. 

First, whitening the ends, lay out the bases of 
the prism. Find the centre of each end by draw- 
ing diagonals, and mark it 
lightly with a centre punch. 
With a compass, draw round 
this the inscribed circle. 
From a, Fig. 67, draw a line 
on the rectangular face of 
Fig. 67. the prism, parallel to the 

edge, thus finding the corresponding point on the 
other base, and draw the inscribed circle. Start- 
ing from a^ lay off chords equal to the radius, find- 
ing thus the points h, c, 4 e,f. Draw the hexagon 
on each end of the piece. Connect the vertices 
aa and dd of the two hexagons, by lines drawn 




CHIPPING. 123 

on tlie faces of the block. Prolong ah, dc, af, de^ as 
in the iigure. Connect the points gg^ 
lili, ii^ Ilk, of the two bases by lines on Laying out a 
the faces of the block. If now you cut hexagonal 
oft' first the four pieces which have the P"^"^- 
bases amg, had, doi, and alk, you will make a hex- 
agonal prism, whose bases, however, are not regu- 
lar. On the faces of this prism draw hh, cc, ee, and 
ff\ and cut away the parts whose bases are hghc 
and kfei, and tlie prism will be complete. 

To cut off all these parts, first hold the block 
endways in the vise, its edges perpendicular to the 
jaws and the line (^/'^ parallel to them. Beginning 
near m, cut oif a piece along the whole edge mmy 
just as in the last exercise. As the chisel ap- 
proaches the end of the cut, turn the piece round 
and cut in the opposite direction, so as not to 
splinter the base. Repeat this till you have cut 
down to ag, being careful not to go beyond. The 
first cuts, being narrow, may be deeper than the 
succeeding ones. Repeat this operation at the 
other three corners. Then, having drawn the 
new lines bh, cc, ee^ff, cut oif the remaining por- 
tions in the same way. If you have not cut quite 
down to the required surfaces at first. Exercise 40. 
you may use a thinner and sharper Chipping 
chisel and a lii^hter liammer for the ^^^^^" 
finish, making constant use of a straight-edge and 
a "template" or plate of brass, Fig. 68, whose 



124 FIRST LESSONS IN METAL-WORKING. 

angle is 120°, to make sure that you are not cut- 
ting anywhere too deep. Having made one face 
as straight and smooth as possible, and free from 
winding (Wood- working, page 54), apply the tem- 
plate repeatedly to this w^hile working the next 
face, so as to give the next the proper inclina- 
tion to this. When the two faces adjacent to the 
first are finished, give the next two the proper 
inclination to these. If this has been correctly 
done it will be easy to give the last face the 
proper inclination to the two preceding ones. In 




Fig. 68. 

applying the template, it is of the utmost impor- 
tance that both arms of it should be exactly per- 
pendicular to the edge of the prism which lies be- 
tween them ; otherwise you will make the angle 
of the prism too obtuse. Very close attention to 
this is absolutely necessary, as is also perfect cor- 
rectness in the angle of the template itself. Of 
course, if the two bases have been drawn exactly 
correct and with their corresponding sides parallel, 
you have only to cut down to these lines and then 
work with the straight-edge alone, the tem23late 



CHIPPING. 125 

being uu necessary ; but your work will hardly be 
exact enougli for this. 

The faces of the prism being finished, the bases 
are to be cut off in the same way, perpendicular 
to the faces, and ^^-^" apart, the work being tested 
as it proceeds \vith straight-edge and square. The 
result should be a true hexagonal prism Syig'^ high, 
its opposite faces being equal and parallel rectan- 
gles, its edges straight, and its angles all equal to 
that of the template. There should be no marks 
extending conspicuously below the general sur- 
face so that they cannot be easily removed by the 
file, as in a later lesson. 



126 



FIRST LESSONS IN METAL-WORKING. 



LESSON XX. 



DEILLIJSTG ATn^D SAWING. 



In the chipping exercises just finished, no large 
amount of metal had to be removed, though the 
quantity to be cut away was larger than it would 







^^ 






J • -1^ — 


S-cmr >■ 




^ ( 


) 


f 


B 





Fig. 69. 



be proper to attack with the file. In some cases 
a larger piece has to be removed, as when a cor- 
ner is to be cut out of a block of metal A^ or a 
slot to be made in one, as J3. In such a case the 
piece is cut out with a " hack-saw," Fig. 70. The 
teeth of this saw have their front edges perpendi- 
cular to the edge of the saw, and their back edges 
inclined to it, as in the rip-saw (Wood- working, p. 



DRILLING AND SAWING. V21 

88). They therefore cat under the metal, some- 
what as a chipping-chisel does, removing the metal 
in small chips, like the saw dust from a wood-saw. 
Its teeth have no "set," as those of wood-saws 
generally have, but are sometimes made a little 
thicker than the back of the blade, by setting the 
saw up on its back edge on a block of hard wood 
before sharpening it, and hammering the points 




Fig. 70. 



of the teeth lightly. This not only spreads them 
out sideways and gives the tool the extra thick- 
ness on the edge which makes it run freely, but 
at the same time brings the points of the teeth 
into a straight line. This is very essential to the 
proper working of a saw, whether in wood or in 
metal. If any of the teeth stand up above the 
rest, they catch in the work and make the saw 
jump and " chatter." Sometimes this thickening 
of the edge of the teeth is omitted, the " burr" or 
roughness left by the file being sufficient to give 
the needed " set." 

The cutting of the slot B, Fig. 69, Exercise 41. 

in a plate of h" brass will be a good Drilling, 
exercise in the use of the saw and of the " ratchet- 



128 



FIRST LESSON'S IN METAL- WORKmO. 



drill." The slot is commenced by boring two holes 

for its ends with the 
hand-drilling machine, 
Fig. 71, or the ratchet- 
diill, Fig. 72. Mark 
the exact positions of 
the centres of the holes 
with a centre-punch. 
Provide a drill 1 cm. 
wide, such as you made 
in Exercise 37. If you 
have not one of exactly 
the ri2:ht width, alter a 
wider one^ by reducing 
it on the grindstone, 
being careful to reduce 
both sides equally. 

The ratchet-drill is 
made in various forms, 
but the essential prin- 
ciple of all is the same. The work to be 
drilled rests, at A^ on blocks supported on the 
frame-work B, which may be screwed to the 
bench. A screw (7, which must be turned by 
hand as the boring progresses, or else a l^ver 
worked by the hand of an assistant, presses the 
drill D down. A lever or handle E^ provided 
with a spring " pawl " concealed in the box F, 
turns on the axis or shaft of the drill. The pawl 




Fig. 71. 



DRILLING AND SAWINO. 



129 



slips by the teetli of a tootbed wheel which is at- 
tached to the axis, when the handle is turned in 
one direction, but catches the teeth and turns the 
drill when moved in the opposite direction. The 
hand-drilling machine, Fig. 71, is used for the 
same purpose, and is even more convenient. 




Tgrrgr 

Fig. 72. 

Setting the plate on the bottom of the frame- 
work of the drill, and supporting it on blocks, if 
necessary, to raise it to the pi-oper height, turn the 
screw at the top till you bring the point of the 



130 FIRST LES80N8 IN METAL-WORKING, 

drill down into the hole made by the centre-punch. 
Fasten the work so that it cannot turn. Turn the 
drill by means of the handle, and keep moving it 
down at the same time by means of the " feed "- 
screw. Lubricate the point with oil or with soap 
and water in cutting brass, wrought-iron, or steel ; 
for cast-iron this is not necessary. Do not " feed " 
or force the drill forward too fast, or you will 
break it, or spoil its temper. Let the drill, when 
it comes through, come out into a hole in the sup- 
port, or else have a block of wood immediately 
under the work. 

The tw^o holes being bored, draw two parallel 
lines tangent to them with the scriber, thus mark- 
Exercise 42. ^^o ^^^ ^^^^ ^^^^ shape of the piece to 
Cutting a be rcmovcd. Holding the piece in the 
^^°*" vise, and using a square file, cut one of 

the holes to the shape shown in Fig. 73, forming 

thus flat sides against which 
the sides of the saw can rest. 
Loosening the screw at the 
end of the saw-frame, un- 
hook the saw, put the blade 
through the hole, hook it and 
^^^- '^'^- tighten it again, and cut down 

to the other hole. Use oil to make the saw work 
freely, except in cast-iron. Do not press too hard, 
and be careful not to run outside of the line. 
The first cut being made, carry the saw back 



Q 



DRILLING AND SAWING. 131 

to the first bole, and cut tlie second line in the same 
way. The piece between the lines being removed, 
the roughly framed slot can be finished >vith the 
file as in the next lesson. 

Such a piece is sometimes removed by boring 
a series of holes close together along the whole 
length of the slot, and then cutting away the metal 
between them with a round file. 



132 FIRST LE8S0N8 IJST METAL- WORKING. 



LESSOJST XXI. 
FiLnsra. 

After chipping and sawing, the work is ready 
to be smoothed w4th the file. 

The iile is a series of small chisels, finer or 
coarser according to the work required of them. 
These minute chisels are made by cutting numer- 
ous fine grooves very close together in a bar of 
steel shaped as in Fig. 74. If only one such set 
of grooves is cut, the file is called a '^ single-cut " 
file or "float," and appears as shown in the upper 
part of Fig. 74, a. The appearance of the teeth 
is shown, magnified, at d. The w^hole face of the 
file is thus a series of chisels, each having a breadth 
equal to the length of one of the lines in a, inclined 
to the axis of the file at an angle of 35° to 55°, 
and having their sharp edges turned towards the 
point of the file. Files of this sort are only used 
for soft materials, such as wood, horn, and lead. 
When very coarse, as in the case of the files used 
for lead, the cuts are almost 23erpendicular to the 
length of the file. The files used for such work 
as you will undertake, or for metal-work in gen- 



FILING. 



133 



eral, have two such sets of grooves, and are called 
"double-cut." The first cuts are made as already- 
described, and the second, which are not quite so 
deep, cross these, as show^n in the lower part of 



U 

Fig. 74. 

the figure, being inclined to the axis in a direction 
opposite to the first, at an angle of from 75° to 85°. 
The wide chisels of the first cut are thus divided 
into a large number of small-pointed teeth. The 
teeth of any one row being pushed across the 



134 FIR8T LESSON'S IN METAL-WORKINO. 

work would make a series of fine grooves ; but the 
teetli of the next rows following these, cut down 
the ridges between these grooves, and so gi'adually 
plane the work down. 

Double-cut files have various names to distin- 
guish the degrees of fineness or the closeness of 
the grooves. These names differ somewhat in 
the different regions in which files are .made, the 
Lancashire names and the Sheffield names, for 
instance, being not exactly the same. Without 
learning both series of names it will be sufficient 
to remember that, in both sets, the coarsest files 
are called ^^ rough," and the very fine ones 
'^smooth." Intermediate ones, following the rough, 
are ^'bastard" and "second-cut," and a still finer 
kind than the smooth are called ^' dead-smooth" or 
"superfine." 

It may be remembered also that the "rough" 
Lancashire files have from 21 to 56 cuts to the 
inch, the "smooth" from 56 to 112, and the "su- 
perfine" as many as 300 in the case of the small- 
est files. "^ 

The grooves are cut with a chisel while the file 
is soft, and it is then hardened and tempered ac- 
cording to the kind of work it is to do, and the 
"tang" or pointed end is softened to prevent its 
breaking. 

The description of the mode of cutting the 

* Holzapfel: Turning and Mechanical Manipulation. 



FILING, 135 

teeth of a clouble-cut file, or an inspection of the 
teeth with a mao:nifvino^-2^1ass, will convince you 
that files are delicate tools, and that they can be 
easily injured by improper treatment. A few 
precautions may be given here to enable you to 
avoid the commonest errors, and others will 
come to your notice afterwards, as your work pro- 
gresses. 

1. A new file must not be used on wrought-iron 
or steel. These can be cut with a file that is 
partly w^orn, but cast-iron and brass require new 
and sharp files. 

2. No file, unless it be one that is almost worn 
out, should be used on chilled castings. The sur- 
face of a casting should be carefully tried with an 
old file, and if it is found to be very hard, the 
skin must be removed on the grindstone. 

3. No file should be used on castings, whether 
hard or soft, in the state in which they come from 
the foundry. The surface is covered with sand, 
which will spoil any file. This is sometimes re- 
moved by " pickling" in dilute sulphuric acid, 
which eats away a portion of the iron and loosens 
the sand so that it can be washed off. When the 
figure of the casting is such that the surface can- 
not be reached by the grindstone, this is the only 
effectual method, excej^t chipping, of preparing 
the work for the file. 

4. The file should always be relieved from pres- 



136 



FIRST LES80N8 IN METAL-WOBKINO. 



sure while it is being drawn back, as lieavy pres- 
sure on tlie backs of tke teetb breaks tkem oft*. 
It is not necessary, however, to lift the file from 
the work, but only to lessen the pressure. 

5. The teeth of the file should be ke]3t clean. 
They are apt to become " clogged, or " pinned " by 




(T 



Fig. 75. 

the dust cut off, which must then be removed. 
This can be done in several ways. The "pins" 
may be pushed out with a pointed steel wire, Fig. 
75, A. They may be brushed out with a wire file- 
brush, B, of fine brass or steel wire, bound into a 
bundle with the ends projecting; or they may be 
raked out with the scraper, c, made of a piece of 
sheet-brass hammered to an edge and bent at right 




FILING. 137 

angles, into whicli the teeth of the file will cut 
when it is drawn over them, allowing the inter- 
mediate points to penetrate into the grooves and 
clear them. 

The file should be fitted w^th a handle of soft 
wood. To put the handle on, hold the file in the 
vise, protecting it from the 
steel jaws by false jaws 
of lead, A, Fig. 76, and 
leaving the tang project- 
ing forward. Then, tak- ^^^- ^^• 
ing the handle in the hand, push the tang into it, 
turning the handle at the same time, to let the 
tang bore its way. Take the handle oif and 
knock out the shavings, and repeat the operation 
till the tang has entered about three quarters of 
its length, or a little more, leaving the rest for 
future use as the handle wears loose. The handle 
is sometimes fitted by heating the tang to redness 
and pushing it in, letting it burn its way. This 
method is objectionable, however ; first, because 
of the risk of overheating the file, and secondly, 
because the charred wood wears away soon, and 
lets the handle come loose. 

Besides the differences in the teeth of files, there 
are differences in size and shape, adapting them 
to different kinds of work. The files that will be 
most useful in snch work as you will do are such 
as are shown in Fig. 74, and are called "taper- 



138 FIRST LESSONS IN METAL-WORKING. 

flat." Their cross-section is rectangular; but they 
are not of equal section throughout, being tapered 
both in breadth and thickness, and swelled or 
"bellied" in the middle. They vary in length 
from about 4 to 24 inches, and will be most con- 
venient for your work if about 10 to 12 inches 
long. With such a hie you may now produce a 
smooth, plane surface on the cast-iron block of 
Exercise 37. Use a somewhat coarse file for the 
first steps of the work, and afterwards, for finish- 
ing, a finer one. Put the block in the vise with 
Exercise 42. ^^^^ chippcd face about \" to \" above 
Filing a the Jaws. For work such as this the 

plane surface. ^^-^^ ought to be at such a height as to 

bring the work about to the level of the elbow. 
For much larger work it should be lower, to 
enable you to throw the weight of the body on 
the file, and for very small and fine work, higher, 
to allow you to see it more distinctly. Spread 
your legs apart a little, clasp the file in the right 
hand, the fingers being below and the thumb on 
top, hold the point of the file between the thumb 
and fingers of the left hand to press it down, and 
push the tool forward. The length of the file 
should point not straight forward, but a little 
towards the left, and the movement of the hand 
should also be a little towards the left as well as 
forward, but with occasionally a few strokes to- 
wards the right to prevent the teeth from follow- 



FILING. 



139 



iug their old tracks and scratching the work too 
deeply. 

The principal difficulty in using the file is to 
move it forward without giving it a rocking mo- 
tion — a difficulty about the same as that encoun- 
tered in using the jack-plane (Wood-working, p. 
64). If you lower the point as you push it for- 
ward and raise it as you draw it back, as you will 
find yourself inclined to do, you w\\\ cut off the 
front and rear edges of the work more than the 
middle, and will produce a curved surface ; but if 
you keep the file quite level and move it with long 
strokes, you will cut equally across the whole 
breadth, and produce a plane surface. Test your 
work with respect to this point from time to time 
as you proceed, by applying a "straight-edge." 
Tt will not be enough to apply the straight-edge 
in one direction, parallel, for instance, to a b, Fig. 
77, because it is possible for the lines a b, c d 
and E F to be all straight, 
and yet the surface not to 
be plane but to have two 
oj^posite corners, as a and 
F, higher than the others. 
Neither is it sufficient to 
apply the straight - edge 
parallel to one of the 
diagonals; but if it is applied parallel to both 
dia2:onals and both edges, it will be impossible for 



H 

Fig. 77. 



140 FIRST LESSON 8 IN METAL-WORKING. 

it to touch along all these lines if the surface is 
warped, or "in winding." Trying the surface, 
therefore, in all directions, and removing the high 
parts carefully with the round or bellied part of 
the file, and with lighter and lighter strokes as 
the piece becomes more and more nearly true, you 
will finish it at length to a true plane, or as nearly 
so as it is practicable to make it with the file. 

As another exercise, involving gi-eacer difficul- 
ties than the last, you may now finish up the 
hexagonal prism of brass made in Exercise 39. 

You will make, 1st, one of the hex- 
Exercise 43. -IT -, T T 1 , 

Filing up a agonal bases plane and perpendicular to 
hexagonal the faccs of the prism ; 2d, the other 
prism. ^^g^ plane, parallel to the first, and at 

the proper distance (2'') from it ; 3d, one of the 
rectangular faces plane, of the proper width, and 
perpendicular to the bases; 4th, two adjacent 

faces plane, of proper width, 
perpendicular to the bases, and 
inclined at the proper angle 
(120°) to the first face; 5th, the 
last three faces plane, parallel to 
the first three, and of the proper 
width. 

First try with a square, as in 
Fig. 78, whether one of the bases 
is pei'pendicular to the six faces. 
If either of the angles is acute, the base is to be 




FILING. 141 

filed off at this place. Holding the block in the 
vise, file the base true as in the last exercise, iisinof 
a coarse file first and afterwards a new and fine one 
and trying the surface in all directions with a short 
thin-edged straight-edge while working, and with- 
out removing the piece from the vise for the pur- 
pose. 

When this surface will bear every test, proceed 
to the next — the opposite base. Since this is to 
be made parallel to the first, whether that is per. 
pendicular to the faces or not, it is to be tested, 
not w4th the square, but with the straight-edge 
and the calipers, Fig. 79. They are opened to the 
width of exactly 2'', and are 
to be applied to the work 
repeatedly as the second sur- 
face approaches completion, 
to prevent the cutting away 
of more than the proper 
amount of metal. Before 
the piece is ready, however, 
for the use of this tool, it is 
to be first marked to the 
proper height, and then cut 
down close to the mai'k. The rectangular faces 
being too rough to show a fine mark, may be first 
filed smooth enough for this purpose. To avoid 
injuring the finished base in this operation, use 
the false Jaws of lead or brass. Be careful, in this 




142 FIRST LESSONS IN MUTAL- WORKING. 

first filing of these faces, to take off no more than 
just enough to enable them to show a fine mark. 
Chalk the sides. Set the piece up on its finished 
base, on a "surface-plate." This is a square plate 
or block of hard cast-iron, which has been finished 
as nearly as possible to a true plane surface, and 
serves as a standard of comparison for other sur- 
faces which are to be made plane. The prism 
being set on this, is held firmly with one hand, 
while the " scriber block" s. Fig. 80, is held on the 
plate with the other hand, and the "scriber- 
point," p, after being set to the exact height of 2'' 
above the base by the screw v, is carried carefully 
round all the faces of the prism, making a fine 
mark. Then, holding the prism in the vise, cham- 
fer the upper base down to this mark, and cut it 
down, first Avith a coarse and afterwards wdth a 
fine file. As you approach the mark, work more 
and more carefully. When very near the mark 
use the calipers frequently at all points of the two 
bases, till the prism measures exactly Exercise 44. 
the right height at all points. Be Use of scriber 
careful not to force the calipers, nor ^ndcaUpers. 
yet to make them go on too loosely. They must 
just touch closely, and so that no rattle is possible. 
If the joint is tight, as it ought to be, the width 
between the points will not be altered by sliding 
them on and off repeatedly, unless considerable 
force is used. Furthermore, they must be held in 



FILING. 



143 



the proper 2^<^sitioii while being usea. If one 
point is farther advanced on the surface than the 
other, as at a, Fig. 81, you may work the piece 




Fig. 80. 



too short; and you will do the same if one is in- 
clined to the right of the other, as at b. In short, 
the line joining the two points must be exactly 
perpendicular to the two surfaces, and when it is 



144 



FIRST LESSONS IN METAL-WORKINO. 



held thus, the two points must just touch botK 
surfaces. Finally, the calipers must be handled 




Fig. 81, a. 

carefully, being laid down on the bench gently, 
so as not to alter their adjustment, and must be 




Fig. 81, b. 

occasionally tested by comparison with the rule, 
or with a block already finished to the right size. 
When the distance between the two bases is 



FILING. 145 

everywhere exactly 2", the second surface is parallel 
to the first, and is plane, provided the first is so. 
Yon should not neglect, hoAvever, to apply the 
straiorht-edixe in all directions on the second sur- 
face, as an additional test. This may be done 
without removing the piece from the vise, if you 
stoop down, so as to see under the edge. 

Protecting the finished bases by false jaws, file 
up one of the faces. The process is essentially 
the same as before, but even more care is neces- 
sary, to avoid filing away too much. As all the 
lines previously drawn on the bases have been 
filed away, it will be well to draw them again, 
but very lightly, with sharp-pointed compasses 
and a marking-awl, and then take care not to 
work beyond them. When one of the rectangu- 
lar faces has been finished, the template should be 
used, as well as the straight-edge, in filing the 
others, care being taken, however, to test the cor- 
rectness of the template, and to a^^ply it properly, 
as explained in Exercise 39. 

If properly finished, the prism will stand the 
followino; tests : 

1°. All the surfaces, as tested with the straight- 
edge, will be true planes. 

2°. Each pair of opposite surfaces will be par- 
allel, as shown by the calipers. 

3°. All the faces will be perpendicular to the 
bases, as shown by the square. 



146 FIR8T LESSONS IN METAL- WORKING. 

4°. AH the angles will be true, as measured by 
tbe template. 

5°. All the faces will be of equal width. 

6°. All the edges will be straight and sharp, 
and all the surfaces smooth, and free from coarse 
scratches, showing only the fine and regular marks 
of the file. 

Other methods of producing a finer finish on 
surfaces, known as draw-filing, scraping, grinding, 
oil-finishing and polishing, will be explained here- 
after. 

As a last exercise in filing, finish the slot that 
you began in Exercise 41, making it 84 mm. X 12 
mm. The surface being in this case narrow, con- 
siderable care will be needed to avoid cutting off 
one edge more than the other, and you must look 
frequently at the back of the work to see that you 
are not passing the mark. You will lessen the 
trouble of this part of the work^ if, as in working 
to a mark in general, you first cut, on each side, 
a chamfer down to the mark, which will then 
serve as a guide. The ends of the slot, which 
were left round by the drill, are to be filed square 
with the edge of the file. After the ends are 
finished, if any more work is to be done on the 
sides, for the purpose of finishing up the corners 
sharp and clean, the ''safe edge" of the file which 
has no teeth, should be used in the corner, so as 
to avoid injuring the finished end. If the file hao 



FILING. 147 

BO safe edge, you can make one by gi'indmg off 
the teetli on one edge. This will be even better 
than the safe edge made by the manufacturer, as 
the teeth on the face will come up more sharply 
to the edge, and will finish the comers better. 
The tests of the work are obvious. The sides and 
ends must be straight and plane, and perpendicu- 
lar to the face of the plate and to each other, and 
the slot must be exactly true to the proposed 
dimensions, 84 mm. X 12 mm. 



148 FIRST LESSONS IN METAL- WORKING. 



LESSON XXII. 

SOLDEEING. BUNSEN BUENEE. 

We have now learned how to give approxi- 
mately any desired form to wroiight-iron or steel 
by forging and welding, and to cast-iron, steel, 
brass, zinc, and other easily fusible metals by 
founding. When the approximate form has been 
given, we have seen how to produce small changes 
by chipping and filing. We have now to learn 
another method of building up complex forms by 
uniting simpler pieces, which partakes in part of 
the nature of welding, and in part of that of cast- 

Soldering is uniting two pieces of metal by 
means of another metal. This other metal may 
be, first, one which melts at a lower temperature, 
and which adheres closely to the two pieces or 
partially combines Avith them and thus joins them 
together ; or, secondly, it may be the same metal 
as that of which the two pieces are composed. In 
the first case the operation is very much like that 
of gluing. It is called " soft soldering" when the 



SOLDERING. BUNSEN BURNER. 



149 



solder is an alloy of tin and lead, sometimes with 
the addition of bismuth to make it more fusible ; 
anc! ''hard soldering" when a less fusible material 
is used, as gold, silver, copper, or an alloy of tin 
lead, and zinc, called spelter solder. In tbe second 
case, when the pieces are joined by a portion of 
the same metal, the operation is moi'e analogous 
to welding, and is called "burning" or ''brazing." 
A few examples will make clear the nature of the 
operations and the mode of proceeding. 

For a first exercise, join with soft solder tw^o 
pieces of brass in the manner shown in Fig. 82. 
File the edo-e of the 
piece A straight and 
square. Scrape or file 
the surface of b clean, 
where a is to join it. 
The two are now ready 
for the solder. 

As in welding, so in 
soldering, it is necessary ^^^- ^^- ^^"^^ ^^^^'^ 

that the two surfaces should be clean and free 
from oxide. A flux is therefore used as in weld- 
ing, to carry off the oxide that will be formed on 
the surface when heated, as well as any dirt that 
may be there. Various fluxes are used for differ- 
ent kinds of work, as borax, sal ammoniac, resin 
and muriate of zinc. For this exercise we will use 
the last. It is prepared by dissolving scraps of 



3B 



A 



150 FIRST LESSONS IN METAL- WORKING. 

ziiic in dilute liydrochloric acid. A small wide- 
necked bottle of this solution is kept on the bench 
ready for use. It should have a piece of iron wire 
thrust through the cork and dipping down into 
the fluid. With this a drop or two of the fluid can 
Exercise 45. t>e applied to the surface of a piece of 
Soldering metal as needed. Or, a stouter piece of 
brass with ^'^^^ may be fltted with a wooden handle 
soft solder. and uscd for this purpose, as well as 
for '^ tinning" small surfaces, such as those of this 
exercise. For the latter purpose the wire must it- 
self be tinned at the end. To tin the wire, dip it 
into the solution, then hold it in the flame of the 
Bunsen burner, the outer tube of the burner being 
turned so as to admit plenty of air, giving a blue 
flame. If the air supply is insufficient, the flame 
will be yellow and smoky, and not so hot. Rub 
the end of the wire with the solder-stick, using 
the " tin-solder" compound of 3 parts of tin to 2 
of lead, or 2 of tin to 1 of lead. The solder will 
adhere to the surface wherever it is clean. If 
there is any spot where it does not adhere, it nmst 
be cleaned with the file or a piece of sandstone, 
and the operation repeated. With the tinned wire 
we can now tin the surfaces of the brass. Hold 
the piece a in the flame with pliers. Apply a 
drop of the flux to the edge with the tinned wire, 
and as it boils off rub the wire to and fro alonsr 
the edo-e till the latter is covered with a brio^ht 



SOLDERING. BVN8EN BURNER. 



151 



clean layer of the solder ; or, toucli it witli the sol- 
der stick till a drop of the solder adheres, and 
then spread it along the edge with the wire. With- 





FiG. 83. 



draw it from the flame and let it cool. Tin in the 
same way the portion of b on which a will rest. 
The two surfaces will now unite, if held together 




152 FIRST LESSON'S IN METAL- WORKING. 

wMle the solder is melted. They may be held 
together in various ways. 

1. The piece b may be laid on a retort-stand, 
Fig. 83, and the piece a set up on it at the proper 
place. The fiame being then applied below b, 
the solder will melt, and then, the ilame being re- 
moved, the piece will cool. As the two surfaces 
of the solder are somewhat round, it is difficult to 

make the thin piece a stand 

upright. It may be held 

down during the melting 

with a pointed wire, or still 

better by means of a wire 

spring of hard brass, as in Fig. 84. In either case 

it will be best to file the two round surfaces of the 

solder flat before putting them together. Or, 

2. The pieces may be held, one in each hand, 
with a pair of pliers, [and pressed lightly to- 
gether in the flame till the solder melts, and then 
removed to cool. Or, 

3. Clamped together by the spring as in case 1, 
they may be held in the flame wdth a pair of 
pliers, and soldered and cooled as before. 

With such light pieces as these the last method 
will probably be found the most convenient. If 
the piece a were considerably heavier, and broader 
at the base, its own weight would keep it in posi- 
tion, and no special device would be needed for 
holding it. 



SOLDERING. BUN SEN BURNER. 153 

The two pieces of this exercise may be soldered 
without previous tinning, if the surfaces are thor- 
oughly clean. Hold the pieces together with a 
spring, as before. Taking b in the pliers with 
the left hand, put a drop or two of flux, and a few 
small chips of solder cut off with a knife, in each 
of the angles. Heat the pieces in the flame. First 
the flux will flow into tlie joint and afterwards 
the solder. If the solder does not spread along 
the whole length of the joint, draw it along with 
the end of the fine wire which is in the bottle. 
Cool as before. 

In whichever way the pieces are prepared and 
heated, the principal points to be heeded are : 

1. To have the surfaces quite clean. 

2. Not to allow the pieces to be displaced by 
the boiling of the flnx or the melting of the solder. 

3. Not to hold the pieces in the flame longer 
than is necessary to melt the solder, as overheat- 
ing burns the solder and weakens the joint. 

4. Not to disturb the pieces till the solder has 
" set," or hardened. The moment of setting can 
generally be observed by watching closely. At 
this moment the bright surface of the solder be- 
comes dulled by the formation of a multitude of 
minute wrinkles as the metal contracts. The 
cooling may be hastened, in the case of very light 
pieces, by blowing, and in that of heavier pieces 
by applying a few drops of water. 



154 



FIRST LE8S0N8 IN METAL- WORKING. 



5, IN^ot to use too much solder. Besides being 
wasteful, this fills up the angle, and the excess 
will have to be filed away to make a neat job. 

Where gas cannot be used, the exercises of this 
lesson can be performed Avitli a blow-pipe (as in 
Lesson XXIV) or with a blast-lamp, Fig. 85. 
This is an alcohol lamp, a, ^vhich burns under a 
vessel of alcohol, b. The alcohol in b boilins^, 




Fig. 85. 

drives off first the air and then alcohol vapor 
through the tube c, thus blowing a strong blast 
through the fiame of the lamp, and shooting out a 
tongue of hot flame which can be directed on the 
work. If the lamp alone is used, and the blast is 
produced by blow^ing with the mouth through a 
bent tube, the instrument becomes an ordinary 
blow-pipe. 



SOLDERING. BUN8EN BURNER. 155 

It is obvious that such a joint as that in the 
last exercise cannot have any very great strength. 
It will nevertheless often be useful when, as in 
experimental work in the physical laboratory, it 
is desired to put two pieces together quickly, and 
strength is not important. 

Let us nov/ look a little more closely into the 
strength of a soldei'ed joint. Join two pieces of 



Fig. 86. (Full size.) 

brass with a " lap-joint" as in Fig. 86, cleaning 
and tinning the surfaces, and holding them to- 
gether in the flame with a pair of pliers. Put the 
jointed strip into the small testing-machine (Wood- 
working, Fig. 8, p. 19), and pull till Exercise 46. 

the joint breaks. Record the force Testing a soi- 
used. Put one of the pieces into the d^^^^J^i^t- 
machine and break it, and record the force used. 
Find, 

1. How^ many times stronger the brass is than 
the soldered joint. 

2. How many times stronger the brass is than 
a soldered joint of the same area as the cross-sec- 
tion of the brass ; and thence, 



156 FIRST LESSONS IN METAL- WORKING. 

3. How large the joint should be to be just as 
strong as the brass. 

Then make another joint of the same kind, 
with a lap just sufficient to make the joint as 
strong as the metal. Test the metal and the joint 
in the machine and record the result. You will 
know henceforth how large a joint surface to al- 
low, with this kind of solder and this kind of 
brass, if you wish the joint to be as strong as the 
metal. Stronger than the metal it is not worth- 
while to make it. 



SOLDEIUNO. THE SOLDERING IRON. 157 



LESSON XXIII. ] 

SOLDERmG. THE SOLDERING-IEON. 

Whett the pieces are large, it is convenient and 
usual to heat only the part which is to be soldered, 
leaving the rest cool. This is done with the" bit" 
or "soldering-iron." 

The iron is first to be tinned. Heat it to a dull 
red on a charcoal fire, or over a large Bunsen 
burner. File the sides bright, quickly. Exercise 47. 
Rub it on a piece of board sprinkled Tinning a soi- 
with powdered sal-ammoniac or resin, enng-iron. 
and then on a plate of copper on which are some 
chips of solder. Wipe it clean with a rag. If 
you have allowed it to fall below the temperature 
at which solder melts, the operation will fail, and 
reheating will be necessary. If afterwards, in 
using the soldering-iron, you overheat it, the tin 
will burn off, and you will have to tin it again. 

We will now make a joint somewhat like that 
in Exercise 45, but longer and stronger, and be- 
tween two sheets of tin (that is, tinned iron), ar- 
ranged as in the isometric sketch. Fig. 87. Mois- 



158 FIBST LESSONS IN METAL- WORKING. 

ten the angle c between the two pieces witli flux, 
or sprinkle it with powdered resin. Scatter along 
it small chips of solder. Hold the piece a down 
firmly at one end with the end of a file, or any 
pointed tool, and melt a drop of solder in the 
angle. This will fasten or " tack" the piece at 
one end. Tack it in the same way at the other 




__,< 2^ > 

Fm. 87. 

end. This will hold it in place while yon finish 
the job. Hold the piece level, or inclined in such 
Exercise 48. a way that the solder shall run into 
Soldering the joiut. Draw the bit slowly along 

with the sol- .^ t ij.* ii ii n 

derin«r.iron ^^^ angle, melting the solder and caus- 
Tin on tin. ing it to run into the joint. If any part 
is missed, go over it again in the same way. 

The two sheets of metal in the last exercise are 
in planes perpendicular to each other. In this 
case, when the joint is at the edges of both pieces, 



SOLDERING. THE SOLDERING IRON. 159 

it may be made as in Fig. 88, a or b. The joint 
A would be tacked and soldered as in the exercise 
just finished. In b the lower piece should be 
closed tightly on the uppei' with the hammer, and 
then soldered along both the 
exterior and the interior an- 
gle. The manner of bending a 

the sheets for this exercise 

and the last will be explained ' 
in connection with the next. 

When the two sheets are 
to be in the same plane, there b 

are several ways in which 
they may be joined. These ' ^^^ 

are shown in Fig. 89. ^ig. 88. (Full size.) 

The joint a is called the lap-joint. It needs 
but to be tacked at two or three points, as in Ex- 
ercise 48, and soldered as there described. 

B is a " cramp-joint." The edge of the left- 
hand piece is tliinned almost to a knife-edge by 
hammering on a small anvil. The edge of the 
other is nicked obliquely with the shears, and the 
pieces between the cuts are turned alternately u]^) 
and down. The thinned piece is pushed into the 
V-shaped space thus made, and the "cram^^s" are 
hammered down on it. It is then tacked and 
soldered. 

The edges of the two pieces in c, as well as in 
B, Fig. 88, and a, Figs. 87 and 88 are prepared 



160 



FIRST LESSONS IN METAL- WORKING. 



on a tool called tlie ^^hatchet-stake," Fig. 90, 
which is set in a hole in the top of the work- 
bench. The sheet is laid on the edge ab at a 
proper distance from the edge of the sheet, and 
turned over by blows of a flat mallet, the edge 





Fig. 89. (Scale i.) 



being either turned up at right angles to the 
sheet, or doubled over on it, according to the 
kind of joint proposed. 

As an exercise in this kind of soldering, and 
one in which a watei'-tight joint is required, make 
a cubical box of tin or sheet brass, whose edges 



SOLDERING. THE SOLDERING IRON. 



161 



shall have the length of one decimeter exactly, 
inside. Such a vessel will be a " liter" measure. 

The bottom must be cut to the form and dimen- 
sions shown in Fig. 91, a, and must be bent up- 
ward, at right-angles, along the dotted Exercise 48. 
lines. The sides are shown at b, and a cubical 
are to be bent at right angles along 
ad, dc, and ch, and doubled along ah. The notches 



c 



r 



n 



Scale, H 



Fig. 90. (Scale i) 

at the corners show where pieces must be cut out 
to let the upturned edges lie flat. The dimensions 
in the figure are those that all the pieces should 
have if the material had no thickness. Owing 
to the thickness of the metal these must be 
slightly altered, and the amount of the alteration 
will depend on the thickness. If the bottom is 



162 



FIR8T LESSONS IN METAL- WOMKING. 



put on outside of the otlier pieces, it will be necl 
essary to make its inside dimensions larger by 
twice the thickness of the metal. Furthermore, as 



k 



-10 cm 



-. .-A 



J 



J. 



-^T 



JZ 



h- 



- -12-cm.- 



-12 cm.-' 



.i_ 



-^• 



jL 



___-_□ 



,=^- 



'-^ 



d 



:x:.i 



k— 



— lOcra. 

Fig. 91. 



two opposite sides of the vessel are turned over the 
other two, they also must be made wider by twice 
the thickness, and all the sides must be higher by 



SOLDERING. THE SOLDERING IRON. 163 

once the thickness. It ^\W\ be well to cut out the 
pieces in card-board and put them together, to 
assure yourself that you can cut them correctly ; 
make the proper allowance for thickness, and put 
them together properly. Then mark out the 
pieces with a " scratch-awl," Fig. 92, and cut them 
out with the shears. Bend the edges of 
the bottom upwards, the upper edges of 
the sides outwards, and the other edges 
inwards, over the hatchet-stake, being care- 
ful to keep them quite straight, and not 
to bruise the sheets. Set the five pieces 
together to assure yourself that they fit 
properly. You will now discover that the 
overturned edges of the lai'ger side-pieces, 
overlapping the smaller side-pieces, pre- 
vent the bottom from going on, and four 
small square pieces have to be cut out from 
the bottom of these. This cut is not 
shown in the sketch, and you must deter- 
mine for yourself its proper size and shape. Cut 
out these pieces with small shears, being careful 
not to make the cuts too large. 

Now lay one of the larger sides on your bench, 
and join the two narrower sides to it as in Exer- 
cise 48, Fig. 87, being careful, in soldering, not 
to miss any portion of the joint. Lay the other 
large side on the bench, and repeat the same 
operation. The four sides are now fastened to- 



164 FIBST LE880N8 IN METAL-WORKING. 

gether, and ready for the bottom. Set the bottora 
in place, and solder it in the same manner. 

When the vessel is finished, all the angles 
should be perfectly square, all the faces flat, and 
all the joints perfectly water-tight and perfectly 
smooth inside and outside, showing no places 
without solder and no lumps of unnecessary solder, 
and the internal dimensions should be exactly 10 
centimeters each way. 



SOLDERING. BLOW- PIPE. 165 



LESSON XXIV. 

SOLDERING. BLOW-PIPE. 

When a very small piece is to be soldered to a 
miicli larger one, it is often convenient to use the 
blow-pipe instead of either the Bimsen burner or 
the soldering-iron, as with this an intense heat can 
be applied on a very small area. As an example 
of such a joint we will solder an elec- Exercise 49. 
trical "binding-post," a, Fig. 93, to a Use of the 
brass plate b. Take a piece of sheet ^^o^-pipe. 
brass about S'^" long, 3*=" wide, and 3™" thick. Make 
the end of the post flat, and clean with the file. 
Scrape or file the portion of the plate at which 
the post is to be attached. Lay the plate on any 
convenient support, and set the post on it. 
Moisten the angle all round with a drop or two 
of the zinc solution, and lay a few granules of 
solder there. Set the Bunsen burner by the side 
of the work, with the bottom of the flame about 
on a level with the plate. Turn the outer tube 
of the burner so as to shut off the supply of air 
at the bottom, giving a yellow instead of a blue 



166 



FIRST LESSONS IN METAL- WORKING. 



flame, and less heat. Holding the blow-pipe ill 
the right hand, with the tip just outside the flame, 
direct the current of air from the mouth through 
the lower part of the flame. This will produce a 
long slender jet of blue flame/in which the tem- 
perature is very high. Direct this on the base of 
the post and the plate adjoining. The flux Avill 
quickly boil away, and the solder will melt and 



E 




2 



Fig. 93. (Full size.) 

run into the joint. Remove the blow-pipe, and let 
the woT'k cool. 

In making a small joint in this w^ay yoa must 
be careful — 

1°. Not to use too much solder. 

2°. ]N"ot to let the flame play on parts of the 
metal which need no heat, as it discolors them. 

3°. Not to continue the heat longer than neces- 
sary. 



SOLDERING. BLOW-PIPE. 167 

4°. Not to let the small piece be displaced by 
the boiling of the flux. Hold it down with a piece 
of wire if necessary. 

There is sometimes a still greater necessity than 
in the last exercise of preventing the S23read of 
heat to other parts than that at which the joint is 
to be made. A good example of this is in the 
case of the soldering of a spring a, such as you 
made in Exercise 36, to the plate b. Fig. 94. If 




Fig. 94. (Full size.) 

the spring is overheated, its temper will be 
" drawn," and the spring spoiled. This may be 
avoided by " sweating" the spring on the plate. 
Tin the plate, at the proper point, over Exercise 50 
the Bunsen flame. Then hold the Sweating a 
spring in place by means of a clamp a, '^°^^^' 
Fig. 95, made by filing or sawing a slit in a piece 
of brass or copper. Apply flux and bits of solder 
along the edge of the joint. Hold the clamp, not 
the plate, in the Bunsen flame, and watch the solder 
closely. The heat conducted along the clamp wnll 
reach the plate and melt the solder. As soon as 
this happens, remove the work from the flame, 
and cool it off before there is time for the spring 
to be heated. 



168 



FIRST LESSORS IN METAL- WORKING. 



The exercises 45 to 50 illustrate the principal 
methods of uniting small pieces by means of soft 
solder, or such as melts at temperatures below 
about 450° F. Joints with such solder are, as you 
have found, not very strong, and when great 
strength is important, or w^hen the joint may be 
exposed to much heat when it is used, a hard sol- 
der must be employed. Hard solders, instead of 
being made of lead and tin, are commonly made 




Fig. 95. (Full size.) 

of copper and zinc, or of copper and silver, called 
silver solder. They require a higher temperature 
to fuse them, and the management of them, w^hich 
is somewhat more difficult than that of the soft 
solders, may be deferred to a later stage in your 
study, along with brazing and burning. 



ALPHABETICAL INDEX. 



Bending, 13. 

Blast-lamp, 154. 

Blow-pipe, i65. 

Bunseu burner, 148. 

Calipers, 144. 

Cape-chisel, 114. 

Casting, 70. 

Chipping, 111. 

Cold chisel, making a, 100. 

Cold-chisel, angle of, 104. 

Cross cut Chisel 114. 

Countersinking. 21. 

Cramp- joint, 159. 

Diawing and Pointing, 9. 

Drill, making a, 108. 

Drilling, 120. 

Drilling-machine, Hand. 129. 

Eye, making an, Ki. 

Files, care of, l:i5. 

Files, varieties of, 133. 

File-brush, 136. 

Filing, 132. 

Filing a Plane Surface, 139. 

Fire, care of. 7. 

Flask (moulding), G6. 

Flat ten in >r, ?5. 

Flatter, 50. 

Fuller, 47. 

Hack-saw, 127. 

Hardee, 5. 

Hatchet-slake, 101. 

Helper, 45. 

Hot Chisel. 53. 

Iron, case-hardened, 112. 

Iron, cast, manufacture of, Gl 

Iron, cast, varieties of, 63. 



Iron, cast and wrought, proper- 

ties of. 4. 
Iron, chilled, 111. 
Iron, malleable, 113. 
Iron, pig, 62. 
Iron, puddling, 73. 
Iron, refining, 73. 
Iron, rolling, 72. 
Iron, strength of, 58. 
Ii'on, testing, 59. 
Iron, wrought, manufacture of, 

71. 
Jaws of Vise, false, 137. 
Lap-joint, 155. 
Link, maldng a, 43. 
Melting, temperatures of, 3. 
Moulding, 67. 
Oil, annealing with, 107. 
Oil, hardening with, 107. 
Pattern-making, 65. 
Pointing, 9. 
Prism, making a Hexagonal, 123, 

140. 
Punch, 20. 
Punch, Centre, 20. 
Punching, 18. 
Ratchet drill, 128. 
Scarfing, 38. 
Scarf- weld, 39. 
Scriber, 142. 
Slott, cutting a, 130. 
Soldered Joints, testing, 155. 
Soldering with Blow-pipe, 165. 
Soldering with Bunsen burner, 

148. 
Soldering with soft solder, 157. 

169 



170 



ALPHABETICAL INDEX. 



Soldering with soldering-iron, 

150. 
Split Weld, 51. 
Spring, making a. 106. 
Steel, annealing, 92. 
Steel, colors of heated, 94. 
Steel, hardening, 88. 
Steel, temper indicated by colors 

of, 96. 
Steel, temperature indicated by 

colors of, 95. 
Steel, testing, 79. 



Steel, varieties of, 76. 
Steel, welding high-grade, 85. 
Steel, welding, on sieel, 81. 
Steel, welding, on iron, low- 
grade, 83. 
Sweating, 167. 
Template, 133. 
Tongue-weld, 51 
Twisting, 27. 
Upsetting, 34. 
Welding, 29. 



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